Signaling for inter prediction in high level syntax

ABSTRACT

Systems, methods, and apparatus for video processing are described. The video processing may include video encoding, video decoding or video transcoding. One example method of video processing includes performing a conversion between a video including one or more video regions and a bitstream of the video according to a format rule. The format rule specifies that a variable X indicates whether B slice is allowed or used in a video region. The format rule further specifies that the variable X is based on values of a reference picture list information present flag and/or a field indicating a number of entries in a reference picture list syntax structure.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/962,141, filed on Oct. 7, 2022, which is a continuation ofInternational Patent Application No. PCT/CN2021/085772, filed on Apr. 7,2021, which claims the priority to and benefit of International PatentApplication No. PCT/CN2020/083569, filed on Apr. 7, 2020. All theaforementioned patent applications are hereby incorporated by referencein their entireties.

TECHNICAL FIELD

The present disclosure relates to image and video coding and decoding.

BACKGROUND

Digital video accounts for the largest bandwidth use on the internet andother digital communication networks. As the number of connected userdevices capable of receiving and displaying video increases, it isexpected that the bandwidth demand for digital video usage will continueto grow.

SUMMARY

The present document discloses techniques that can be used by videoencoders and decoders for processing coded representation of video usingcontrol information useful for decoding of the coded representation.

In one example aspect, a video processing method is disclosed. Themethod includes performing a conversion between a video having one ormore chroma components, the video comprising one or more video picturescomprising one or more slices and a coded representation of the video,wherein the coded representation conforms to a format rule, wherein theformat rule specifies that a chroma array type field controls aconstraint on a conversion characteristic of chroma used during theconversion.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video pictures comprising one or more video regions and acoded representation of the video, wherein the coded representationconforms to a format rule that specifies the include a deblocking modeindicator for a video region indicative of applicability of a deblockingfilter to the video region during the conversion.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video pictures comprising one or more video slices and/orone or more video subpictures and a coded representation of the video,wherein the coded representation conforms to a format rule thatspecifies that a flag indicating whether a single slice per subpicturemode is deemed to be enabled for a video picture in case that a picturepartitioning is disabled for the video picture.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video pictures comprising one or more video slices and acoded representation of the video, wherein the coded representationconforms to a format rule that specifies that a picture or a slice levelchroma quantization parameter offset is signaled in a picture header ora slice header.

In another example aspect, another video processing method is disclosed.The method includes: performing a conversion between a video comprisingone or more video pictures comprising one or more video slices and acoded representation of the video, wherein the coded representationconforms to a format rule that specifies that a chroma quantizationparameter (QP) table applicable for conversion of a video block of thevideo is derived as an XOR operation between(delta_qp_in_val_minus1[i][j]+1) and delta_qp_diff_val[i][j], whereindelta_qp_in_val_minus1[i][j] specifies a delta value used to derive theinput coordinate of the j-th pivot point of the i-th chroma mappingtable and delta_qp_diff_val[i][j] specifies a delta value used to derivethe output coordinate of the j-th pivot point of the i-th chroma QPmapping table, where i and j are integers.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprising apicture and a bitstream of the video according to a format rule, andwherein the format rule specifies that a presence of a syntax element ina sequence parameter set that indicates a constrain on loop filteringacross subpicture boundaries is based on whether a number of subpicturesin the picture is greater than 1.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more pictures and a bitstream of the video according to a formatrule, and wherein the format rule specifies how to infer a value of asyntax element that is not present, wherein the syntax element relatedto treating a subpicture as a picture for excluding in-loop filteringoperations.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video regions and a bitstream of the video according to aformat rule, and wherein the format rule specifies that a sequenceparameter set includes syntax elements that are related to parameters ofa deblocking filter applicable to a video region.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more pictures comprising one or more slices and a bitstream ofthe video according to a format rule, wherein the format rule specifiesthat a luma quantization parameter delta information and/or a chromaquantization parameter offset is included in both a picture header and aslice header in case that a certain condition is met.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video pictures comprising one or more video slices and abitstream of the video according to a format rule, and wherein theformat rule specifies to include a flag indicating a presence ofmultiple sets of chroma quantization parameter tables in a sequenceparameter set.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video pictures comprising one or more video slices and abitstream of the video according to a format rule, and wherein theformat rule specifies that indication of multiple sets of chromaquantization parameter tables is disabled for a sequence due to thesequence not including a slice of a particular type.

In another example aspect, another video processing method is disclosed.The method includes making a determination, for a conversion between avideo region of a video and a bitstream of the video, about how paddingor clipping is performed for an inter-prediction process at a boundaryof the video region according to a rule; and performing the conversionbased on the determination; wherein the rule is based on at least two of(a) a type of the boundary, (b) a first parameter indicative of whethera wrap-around motion compensation is enabled, or (c) a second parameterindicating whether subpicture boundaries are treated as pictureboundaries.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more pictures and a bitstream of the video according to a formatrule, wherein the format rule specifies that offsets for wrap aroundpadding or clipping for subpictures of a picture are specified at asubpicture level.

In another example aspect, another video processing method is disclosed.The method includes performing a conversion between a video comprisingone or more video regions and a bitstream of the video according to aformat rule, wherein the format rule specifies that a variable Xindicates whether B slice is allowed or used in a video region, andwherein the format rule further specifies that the variable X is basedon values of a reference picture list information present flag and/or afield indicating a number of entries in a reference picture list syntaxstructure.

In yet another example aspect, a video encoder apparatus is disclosed.The video encoder comprises a processor configured to implementabove-described methods.

In yet another example aspect, a video decoder apparatus is disclosed.The video decoder comprises a processor configured to implementabove-described methods.

In yet another example aspect, a computer readable medium having codestored thereon is disclose. The code embodies one of the methodsdescribed herein in the form of processor-executable code.

These and other features are described throughout the present document.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an example video processing system.

FIG. 2 is a block diagram of a video processing apparatus.

FIG. 3 is a flowchart for an example method of video processing.

FIG. 4 is a block diagram that illustrates a video coding system inaccordance with some embodiments of the present disclosure.

FIG. 5 is a block diagram that illustrates an encoder in accordance withsome embodiments of the present disclosure.

FIG. 6 is a block diagram that illustrates a decoder in accordance withsome embodiments of the present disclosure.

FIGS. 7A to 7F show flowcharts for example methods of video processingbased on some implementations of the disclosed technology.

FIGS. 8A and 8B show flowcharts for example methods of video processingbased on some implementations of the disclosed technology.

FIG. 9 shows a flowchart for an example method of video processing basedon some implementations of the disclosed technology.

DETAILED DESCRIPTION

Section headings are used in the present document for ease ofunderstanding and do not limit the applicability of techniques andembodiments disclosed in each section only to that section. Furthermore,H.266 terminology is used in some description only for ease ofunderstanding and not for limiting scope of the disclosed techniques. Assuch, the techniques described herein are applicable to other videocodec protocols and designs also.

1. OVERVIEW

This document is related to video coding technologies. Specifically, itis about the syntax design of APS, deblocking, subpicture, and QP deltain video coding. The ideas may be applied individually or in variouscombination, to any video coding standard or non-standard video codecthat supports multi-layer video coding, e.g., the being-developedVersatile Video Coding (VVC).

2. ABBREVIATIONS

-   -   ALF Adaptive Loop Filter    -   APS Adaptation Parameter Set    -   AU Access Unit    -   AUD Access Unit Delimiter    -   AVC Advanced Video Coding    -   CB/Cb Blue Difference Chroma    -   CR/Cr Red Difference Chroma    -   CLVS Coded Layer Video Sequence    -   CPB Coded Picture Buffer    -   CRA Clean Random Access    -   CTB Coding Tree Block    -   CTU Coding Tree Unit    -   CU Coding Unit    -   CVS Coded Video Sequence    -   DPB Decoded Picture Buffer    -   DPS Decoding Parameter Set    -   EOB End Of Bitstream    -   EOS End Of Sequence    -   GDR Gradual Decoding Refresh    -   HEVC High Efficiency Video Coding    -   HRD Hypothetical Reference Decoder    -   ID Identifier    -   IDR Instantaneous Decoding Refresh    -   IRAP Intra Random Access Point    -   JEM Joint Exploration Model    -   LMCS Luma Mapping With Chroma Scaling    -   MCTS Motion-Constrained Tile Sets    -   MVP Motion Vector Prediction    -   NAL Network Abstraction Layer    -   NUT NAL Unit Type    -   OLS Output Layer Set    -   PH Picture Header    -   PPS Picture Parameter Set    -   PROF Prediction Refinement with Optical Flow    -   PTL Profile, Tier and Level    -   PU Picture Unit    -   QP Quantization Parameter    -   RADL Random Access Decodable Leading (Picture)    -   RASL Random Access Skipped Leading (Picture)    -   RBSP Raw Byte Sequence Payload    -   SAO Sample Adaptive Offset    -   SEI Supplemental Enhancement Information    -   SH Slice Header    -   SPS Sequence Parameter Set    -   SVC Scalable Video Coding    -   TMVP Temporal Motion Vector Prediction    -   VCL Video Coding Layer    -   VPS Video Parameter Set    -   VTM VVC Test Model    -   VUI Video Usability Information    -   VVC Versatile Video Coding    -   WP Weighted Prediction    -   Y Luminance

3. INITIAL DISCUSSION

Video coding standards have evolved primarily through the development ofthe well-known International Telecommunication Union-TelecommunicationStandardization Sector (ITU-T) and International Organization forStandardization (ISO)/International Electrotechnical Commission (IEC)standards. The ITU-T produced H.261 and H.263, ISO/IEC produced MovingPicture Experts Group (MPEG)-1 and MPEG-4 Visual, and the twoorganizations jointly produced the H.262/MPEG-2 Video and H.264/MPEG-4Advanced Video Coding (AVC) and H.265/HEVC standards. Since H.262, thevideo coding standards are based on the hybrid video coding structurewherein temporal prediction plus transform coding are utilized. Toexplore the future video coding technologies beyond HEVC, the JointVideo Exploration Team (JVET) was founded by Video Coding Experts Group(VCEG) and MPEG jointly in 2015. Since then, many new methods have beenadopted by JVET and put into the reference software named JointExploration Model (JEM). The JVET meeting is concurrently held onceevery quarter, and the new coding standard is targeting at 50% bitratereduction as compared to HEVC. The new video coding standard wasofficially named as Versatile Video Coding (VVC) in the April 2018 JVETmeeting, and the first version of VVC test model (VTM) was released atthat time. As there are continuous effort contributing to VVCstandardization, new coding techniques are being adopted to the VVCstandard in every JVET meeting. The VVC working draft and test model VTMare then updated after every meeting. The VVC project is now aiming fortechnical completion (FDJS) at the July 2020 meeting.

3.1. PPS Syntax and Semantics

In the latest VVC draft text, the PPS syntax and semantics are asfollows:

Descriptor pic_parameter_set_rbsp( ) {   pps_pic_parameter_set_id ue(v)  pps_seq_parameter_set_id u(4)   mixed_nalu_types_in_pic_flag u(1)  pic_width_in_luma_samples ue(v)   pic_height_in_luma_samples ue(v)  pps_conformance_window_flag u(1)   if( pps_conformance_window_flag ) {   pps_conf_win_left_offset ue(v)    pps_conf_win_right_offset ue(v)   pps_conf_win_top_offset ue(v)    pps_conf_win_bottom_offset ue(v)   }  scaling_window_explicit_signalling_flag u(1)   if(scaling_window_explicit_signalling_flag ) {    scaling_win_left_offsetue(v)    scaling_win_right_offset ue(v)    scaling_win_top_offset ue(v)   scaling_win_bottom_offset ue(v)   }   output_flag_present_flag u(1)  subpic_id_mapping_in_pps_flag u(1)   if( subpic_id_mapping_in_pps_flag) {    pps_num_subpics_minus1 ue(v)    pps_subpic_id_len_minus1 ue(v)   for( i = 0; i <= pps_num_subpic_minus1; i++ )     pps_subpic_id[ i ]u(v)   }   no_pic_partition_flag u(1)   if( !no_pic_partition_flag ) {  pps_log2_ctu_size_minus5 u(2)   num_exp_tile_columns_minus1 ue(v)  num_exp_tile_rows_minus1 ue(v)   for( i = 0; i <=num_exp_tile_columns_minus1; i++ )    tile_column_width_minus1[ i ]ue(v)   for( i = 0; i <= num_exp_tile_rows_minus1; i++ )   tile_row_height_minus1[ i ] ue(v)   if( NumTilesInPic > 1 )   rect_slice_flag u(1)   if( rect_slice_flag )   single_slice_per_subpic_flag u(1)   if( rect_slice_flag &&!single_slice_per_subpic_flag ) {    num_slices_in_pic_minus1 ue(v)   if( num_slices_in_pic_minus1 > 0 )     tile_idx_delta_present_flagu(1)    for( i = 0; i < num_slices_in_pic_minus1; i++ ) {     if(NumTileColumns > 1 )      slice_width_in_tiles_minus1[ i ] ue(v)     if(NumTileRows > 1 &&       ( tile_idx_delta_present_flag | | tileIdx %NumTileColumns == 0 ) )      slice_height_in_tiles_minus1[ i ] ue(v)    if( slice_width_in_tiles_minus1[ i ] = = 0 &&      slice_height_in_tiles_minus1[ i ] = = 0 & &  RowHeight[SliceTopLeftTileIdx[ i ] / NumTileColumns ] > 1 ) {     num_exp_slices_in_tile[ i ] ue(v)      for( j = 0; j <num_exp_slices_in_tile[ i ]; j++)       exp_slice_height_in_ctus_minus1[j ] ue(v)      i += NumSlicesInTile[ i ] − 1     }     if(tile_idx_delta_present_flag && i < num_slices_in_pic_minus1 )     tile_idx_delta[ i ] se(v)    }   }  loop_filter_across_tiles_enabled_flag u(1)  loop_filter_across_slices_enabled_flag u(1)  } cabac_init_present_flag u(1)  for( i = 0; i < 2; i++ )  num_ref_idx_default_active_minus1[ i ] ue(v)  rpl1_idx_present_flagu(1)  init_qp_minus26 se(v)  cu_qp_delta_enabled_flag u(1) pps_chroma_tool_offsets_present_flag u(1)  if(pps_chroma_tool_offsets_present_flag ) {   pps_cb_qp_offset se(v)  pps_cr_qp_offset se(v)   pps_joint_cbcr_qp_offset_present_flag u(1)  if( pps_joint_cbcr_qp_offset_present_flag )   pps_joint_cbcr_qp_offset_value se(v)  pps_slice_chroma_qp_offsets_present_flag u(1)  pps_cu_chroma_qp_offset_list_enabled_flag u(1)  }  if(pps_cu_chroma_qp_offset_list_enabled_flag ) {  chroma_qp_offset_list_len_minus1 ue(v)   for( i = 0; i <=chroma_qp_offset_list_len_minus1; i++ ) {    cb_qp_offset_list[ i ]se(v)    cr_qp_offset_list[ i ] se(v)    if(pps_joint_cbcr_qp_offset_present_flag )     joint_cbcr_qp_offset_list[ i] se(v)   }  }  pps_weighted_pred_flag u(1)  pps_weighted_bipred_flagu(1)  deblocking_filter_control_present_flag u(1)  if(deblocking_filter_control_present_flag ) {  deblocking_filter_override_enabled_flag u(1)  pps_deblocking_filter_disabled_flag u(1)   if(!pps_deblocking_filter_disabled_flag ) {    pps_beta_offset_div2 se(v)   pps_tc_offset_div2 se(v)    pps_cb_beta_offset_div2 se(v)   pps_cb_tc_offset_div2 se(v)    pps_cr_beta_offset_div2 se(v)   pps_cr_tc_offset_div2 se(v)   }  }  rpl_info_in_ph_flag u(1)  if(deblocking_filter_override_enabled_flag )   dbf_info_in_ph_flag u(1) sao_info_in_ph_flag u(1)  alf_info_in_ph_flag u(1)  if( (pps_weighted_pred_flag | | pps_weighted_bipred_flag ) &&rpl_info_in_ph_flag )   wp_info_in_ph_flag u(1) qp_delta_info_in_ph_flag u(1)  pps_ref_wraparound_enabled_flag u(1) if( pps_ref_wraparound_enabled_flag )   pps_ref_wraparound_offset ue(v) picture_header_extension_present_flag u(1) slice_header_extension_present_flag u(1)  pps_extension_flag u(1)  if(pps_extension_flag )   while( more_rbsp_data( ) )   pps_extension_data_flag u(1)  rbsp_trailing_bits( ) }A PPS RBSP shall be available to the decoding process prior to it beingreferenced, included in at least one AU with TemporalId less than orequal to the TemporalId of the PPS NAL unit or provided through externalmeans.All PPS NAL units with a particular value of pps_pic_parameter_set_idwithin a PU shall have the same content.pps_pic_parameter_set_id identifies the PPS for reference by othersyntax elements. The value of pps_pic_parameter_set_id shall be in therange of 0 to 63, inclusive.PPS NAL units, regardless of the nuh_layer_id values, share the samevalue space of pps_pic_parameter_set_id.Let ppsLayerId be the value of the nuh_layer_id of a particular PPS NALunit, and vclLayerId be the value of the nuh_layer_id of a particularVCL NAL unit. The particular VCL NAL unit shall not refer to theparticular PPS NAL unit unless ppsLayerId is less than or equal tovclLayerId and the layer with nuh_layer_id equal to ppsLayerId isincluded in at least one OLS that includes the layer with nuh_layer_idequal to vclLayerId.pps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_idfor the SPS. The value of pps_seq_parameter_set_id shall be in the rangeof 0 to 15, inclusive. The value of pps_seq_parameter_set_id shall bethe same in all PPSs that are referred to by coded pictures in a CLVS.mixed_nalu_types_in_pic_flag equal to 1 specifies that each picturereferring to the PPS has more than one VCL NAL unit, the VCL NAL unitsdo not have the same value of nal_unit_type, and the picture is not anIRAP picture. mixed_nalu_types_in_pic_flag equal to 0 specifies thateach picture referring to the PPS has one or more VCL NAL units and theVCL NAL units of each picture referring to the PPS have the same valueof nal_unit_type.When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1, the valueof mixed_nalu_types_in_picjflag shall be equal to 0.For each slice with a nal_unit_type value nalUnitTypeA in the range ofIDR_W_RADL to CRA_NUT, inclusive, in a picture picA that also containsone or more slices with another value of nal_unit_type (i.e., the valueof mixed_nalu_types_in_pic_flag for the picture picA is equal to 1), thefollowing applies:

-   -   The slice shall belong to a subpicture subpicA for which the        value of the corresponding subpic_treated_as_pic_flag[i] is        equal to 1.    -   The slice shall not belong to a subpicture of picA containing        VCL NAL units with nal_unit_type not equal to nalUnitTypeA.    -   If nalUnitTypeA is equal to CRA, for all the following PUs        following the current picture in the CLVS in decoding order and        in output order, neither RefPicList[0] nor RefPicList[1] of a        slice in subpicA in those PUs shall include any picture        preceding picA in decoding order in an active entry.    -   Otherwise (i.e., nalUnitTypeA is equal to IDR_W_RADL or        IDR_N_LP), for all the PUs in the CLVS following the current        picture in decoding order, neither RefPicList[0] nor        RefPicList[1] of a slice in subpicA in those PUs shall include        any picture preceding picA in decoding order in an active entry.        -   NOTE 1—mixed_nalu_types_in_pic_flag equal to 1 indicates            that pictures referring to the PPS contain slices with            different NAL unit types, e.g., coded pictures originating            from a subpicture bitstream merging operation for which            encoders have to ensure matching bitstream structure and            further alignment of parameters of the original bitstreams.            One example of such alignments is as follows: When the value            of sps_idr_rpl_flag is equal to 0 and            mixed_nalu_types_in_pic_flag is equal to 1, a picture            referring to the PPS cannot have slices with nal_unit_type            equal to IDR_W_RADL or IDR_N_LP.            pic_width_in_luma_samples specifies the width of each            decoded picture referring to the PPS in units of luma            samples. pic_width_in_luma_samples shall not be equal to 0,            shall be an integer multiple of Max(8, MinCbSizeY), and            shall be less than or equal to            pic_width_max_in_luma_samples.            When res_change_in_clvs_allowed_flag equal to 0, the value            of pic_width_in_luma_samples shall be equal to            pic_width_max_in_luma_samples.            pic_height_in_luma_samples specifies the height of each            decoded picture referring to the PPS in units of luma            samples. pic_height_in_luma_samples shall not be equal to 0            and shall be an integer multiple of Max(8, MinCbSizeY), and            shall be less than or equal to            pic_height_max_in_luma_samples.            When res_change_in_clvs_allowed_flag equal to 0, the value            of pic_height_in_luma_samples shall be equal to            pic_height_max_in_luma_samples.            The variables PicWidthInCtbsY, PicHeightInCtbsY,            PicSizeInCtbsY, PicWidthInMinCbsY, PicHeightInMinCbsY,            PicSizeInMinCbsY, PicSizeInSamplesY, PicWidthInSamplesC and            PicHeightInSamplesC are derived as follows:

PicWidthlnCtbsY=Ceil(pic_width_in_luma_samples÷CtbSizeY)  (69)

PicHeightInCtbsY=Ceil(pic_height_in_luma_samples÷CtbSizeY)  (70)

PicSizeInCtbsY=PicWidthInCtbsY*PicHeightInCtbsY  (71)

PicWidthInMinCbsY=pic_width_in_luma_samples/MinCbSizeY  (72)

PicHeightInMinCbsY=pic_height_in_luma_samples/MinCbSizeY  (73)

PicSizeInMinCbsY=PicWidthInMinCbsY*PicHeightInMinCbsY  (74)

PicSizeInSamplesY=pic_width_in_luma_samples*pic_height_in_luma_samples  (75)

PicWidthInSamplesC=pic_width_in_luma_samples/SubWidthC  (76)

PicHeightInSamplesC=pic_height_in_luma_samples/SubHeightC  (77)

pps_conformance_window_flag equal to 1 indicates that the conformancecropping window offset parameters follow next in the PPS.pps_conformance_window_flag equal to 0 indicates that the conformancecropping window offset parameters are not present in the PPS.pps_conf_win_left_offset, pps_conf_win_right_offset,pps_conf_win_top_offset, and pps_conf_win_bottom_offset specify thesamples of the pictures in the CLVS that are output from the decodingprocess, in terms of a rectangular region specified in picturecoordinates for output. When pps_conformance_window_flag is equal to 0,the values of pps_conf_win_left_offset, pps_conf_win_right_offset,pps_conf_win_top_offset, and pps_conf_win_bottom_offset are inferred tobe equal to 0.The conformance cropping window contains the luma samples withhorizontal picture coordinates from SubWidthC*pps_conf_win_left_offsetto pic_width_in_luma_samples−(SubWidthC*pps_conf_win_right_offset+1) andvertical picture coordinates from SubHeightC*pps_conf_win_top_offset topic_height_in_luma_samples−(SubHeightC*pps_conf_win_bottom_offset+1),inclusive.The value ofSubWidthC*(pps_conf_win_left_offset+pps_conf_win_right_offset) shall beless than pic_width_in_luma_samples, and the value ofSubHeightC*(pps_conf_win_top_offset+pps_conf_win_bottom_offset) shall beless than pic_height_in_luma_samples.When ChromaArrayType is not equal to 0, the corresponding specifiedsamples of the two chroma arrays are the samples having picturecoordinates (x/SubWidthC, y/SubHeightC), where (x, y) are the picturecoordinates of the specified luma samples.

-   -   NOTE 2—The conformance cropping window offset parameters are        only applied at the output. All internal decoding processes are        applied to the uncropped picture size.        Let ppsA and ppsB be any two PPSs referring to the same SPS. It        is a requirement of bitstream conformance that, when ppsA and        ppsB have the same the values of pic_width_in_luma_samples and        pic_height_in_luma_samples, respectively, ppsA and ppsB shall        have the same values of pps_conf_win_left_offset,        pps_conf_win_right_offset, pps_conf_win_top_offset, and        pps_conf_win_bottom_offset, respectively.        When pic_width_in_luma_samples is equal to        pic_width_max_in_luma_samples and pic_height_in_luma_samples is        equal to pic_height_max_in_luma_samples, it is a requirement of        bitstream conformance that pps_conf_win_left_offset,        pps_conf_win_right_offset, pps_conf_win_top_offset, and        pps_conf_win_bottom_offset, are equal to        sps_conf_win_left_offset, sps_conf_win_right_offset,        sps_conf_win_top_offset, and sps_conf_win_bottom_offset,        respectively.        scaling_window_explicit_signalling_flag equal to 1 specifies        that the scaling window offset parameters are present in the        PPS. scaling_window_explicit_signalling_flag equal to 0        specifies that the scaling window offset parameters are not        present in the PPS. When res_change_in_clvs_allowed_flag is        equal to 0, the value of scaling_window_explicit_signalling_flag        shall be equal to 0.        scaling_win_left_offset, scaling_win_right_offset,        scaling_win_top_offset, and scaling_win_bottom_offset specify        the offsets that are applied to the picture size for scaling        ratio calculation. When not present, the values of        scaling_win_left_offset, scaling_win_right_offset,        scaling_win_top_offset, and scaling_win_bottom_offset are        inferred to be equal to pps_conf_win_left_offset,        pps_conf_win_right_offset, pps_conf_win_top_offset, and        pps_conf_win_bottom_offset, respectively.        The value of        SubWidthC*(scaling_win_left_offset+scaling_win_right_offset)        shall be less than pic_width_in_luma_samples, and the value of        SubHeightC*(scaling_win_top_offset+scaling_win_bottom_offset)        shall be less than pic_height_in_luma_samples.        The variables PicOutputWidthL and PicOutputHeightL are derived        as follows:

PicOutputWidthL=pic_width_in_luma_samples−SubWidthC*(scaling_win_right_offset+scaling_win_left_offset)  (78)

PicOutputHeightL=pic_height_in_luma_samples−SubWidthC*(scaling_win_bottom_offset+scaling_win_top_offset)  (79)

Let refPicOutputWidthL and refPicOutputHeightL be the PicOutputWidthLand PicOutputHeightL, respectively, of a reference picture of a currentpicture referring to this PPS. Is a requirement of bitstream conformancethat all of the following conditions are satisfied:

-   -   PicOutputWidthL*2 shall be greater than or equal to        refPicWidthInLumaSamples.    -   PicOutputHeightL*2 shall be greater than or equal to        refPicHeightInLumaSamples.    -   PicOutputWidthL shall be less than or equal to        refPicWidthInLumaSamples*8.    -   PicOutputHeightL shall be less than or equal to        refPicHeightInLumaSamples*8.    -   PicOutputWidthL*pic_width_max_in_luma_samples shall be greater        than or equal to        refPicOutputWidthL*(pic_width_in_luma_samples−Max(8,        MinCbSizeY)).    -   PicOutputHeightL*pic_height_max_in_luma_samples shall be greater        than or equal to        refPicOutputHeightL*(pic_height_in_luma_samples−Max(8,        MinCbSizeY)).        output_flag_present_flag equal to 1 indicates that the        pic_output_flag syntax element is present in slice headers        referring to the PPS. output_flag_present_flag equal to 0        indicates that the pic_output_flag syntax element is not present        in slice headers referring to the PPS.        subpic_id_mapping_in_pps_flag equal to 1 specifies that the        subpicture ID mapping is signalled in the PPS.        subpic_id_mapping_in_pps_flag equal to 0 specifies that the        subpicture ID mapping is not signalled in the PPS. If        subpic_id_mapping_explicitly_signalled_flag is 0 or        subpic_id_mapping_in_sps_flag is equal to 1, the value of        subpic_id_mapping_in_pps_flag shall be equal to 0. Otherwise        (subpic_id_mapping_explicitly_signalled_flag is equal to 1 and        subpic_id_mapping_in_sps_flag is equal to 0), the value of        subpic_id_mapping_in_pps_flag shall be equal to 1.        pps_num_subpics_minus1 shall be equal to sps_num_subpics_minus1.        pps_subpic_id_len_minus1 shall be equal to        sps_subpic_id_len_minus1.        pps_subpic_id[i] specifies the subpicture ID of the i-th        subpicture. The length of the pps_subpic_id[i] syntax element is        pps_subpic_id_len_minus1+1 bits.        The variable SubpicIdVal[i], for each value of i in the range of        0 to sps_num_subpics_minus1, inclusive, is derived as follows:

for(i=0;i<=sps_num_subpics_minus1;i++)

if(subpic_id_mapping_explicitly_signalled_flag)

SubpicIdVal[i]=subpic_id_mapping_in_pps_flag?pps_subpic_id[i]:sps_subpic_id[i]   (80)

else

SubpicIdVal[i]=i

It is a requirement of bitstream conformance that both of the followingconstraints apply:

-   -   For any two different values of i and j in the range of 0 to        sps_num_subpics_minus1, inclusive, SubpicIdVal[i] shall not be        equal to SubpicIdVal[j].    -   When the current picture is not the first picture of the CLVS,        for each value of i in the range of 0 to sps_num_subpics_minus1,        inclusive, if the value of SubpicIdVal[i] is not equal to the        value of SubpicIdVal[i] of the previous picture in decoding        order in the same layer, the nal_unit_type for all coded slice        NAL units of the subpicture in the current picture with        subpicture index i shall be equal to a particular value in the        range of IDR_W_RADL to CRA_NUT, inclusive.        no_pic_partition_flag equal to 1 specifies that no picture        partitioning is applied to each picture referring to the PPS.        no_pic_partition_flag equal to 0 specifies each picture        referring to the PPS may be partitioned into more than one tile        or slice.        It is a requirement of bitstream conformance that the value of        no_pic_partition_flag shall be the same for all PPSs that are        referred to by coded pictures within a CLVS.        It is a requirement of bitstream conformance that the value of        no_pic_partition_flag shall not be equal to 1 when the value of        sps_num_subpics_minus1+1 is greater than 1.        pps_log 2_ctu_size_minus5 plus 5 specifies the luma coding tree        block size of each CTU. pps_log 2_ctu_size_minus5 shall be equal        to sps_log 2_ctu_size_minus5.        num_exp_tile_columns_minus1 plus 1 specifies the number of        explicitly provided tile column widths. The value of        num_exp_tile_columns_minus1 shall be in the range of 0 to        PicWidthlnCtbsY−1, inclusive. When no_pic_partition_flag is        equal to 1, the value of num_exp_tile_columns_minus1 is inferred        to be equal to 0.        num_exp_tile_rows_minus1 plus 1 specifies the number of        explicitly provided tile row heights. The value of        num_exp_tile_rows_minus1 shall be in the range of 0 to        PicHeightInCtbsY−1, inclusive. When no_pic_partition_flag is        equal to 1, the value of num_tile_rows_minus1 is inferred to be        equal to 0.        tile_column_width_minus1[i] plus 1 specifies the width of the        i-th tile column in units of CTBs for i in the range of 0 to        num_exp_tile_columns_minus1−1, inclusive.        tile_column_width_minus1[num_exp_tile_columns_minus1] is used to        derive the width of the tile columns with index greater than or        equal to num_exp_tile_columns_minus1 as specified in clause        6.5.1. The value of tile_column_width_minus1[i] shall be in the        range of 0 to PicWidthInCtbsY−1, inclusive. When not present,        the value of tile_column_width_minus1 [0] is inferred to be        equal to PicWidthInCtbsY−1.        tile_row_height_minus1[i] plus 1 specifies the height of the        i-th tile row in units of CTBs for i in the range of 0 to        num_exp_tile_rows_minus1−1, inclusive.        tile_row_height_minus1[num_exp_tile_rows_minus1] is used to        derive the height of the tile rows with index greater than or        equal to num_exp_tile_rows_minus1 as specified in clause 6.5.1.        The value of tile_row_height_minus1[i] shall be in the range of        0 to PicHeightInCtbsY−1, inclusive. When not present, the value        of tile_row_height_minus1[0] is inferred to be equal to        PicHeightInCtbsY−1.        rect_slice_flag equal to 0 specifies that tiles within each        slice are in raster scan order and the slice information is not        signalled in PPS. rect_slice_flag equal to 1 specifies that        tiles within each slice cover a rectangular region of the        picture and the slice information is signalled in the PPS. When        not present, rect_slice_flag is inferred to be equal to 1. When        subpic_info_present_flag is equal to 1, the value of        rect_slice_flag shall be equal to 1.        single_slice_per_subpic_flag equal to 1 specifies that each        subpicture consists of one and only one rectangular slice.        single_slice_per_subpic_flag equal to 0 specifies that each        subpicture may consist of one or more rectangular slices. When        single_slice_per_subpic_flag is equal to 1,        num_slices_in_pic_minus1 is inferred to be equal to        sps_num_subpics_minus1. When not present, the value of        single_slice_per_subpic_flag is inferred to be equal to 0.        num_slices_in_pic_minus1 plus 1 specifies the number of        rectangular slices in each picture referring to the PPS. The        value of num_slices_in_pic_minus1 shall be in the range of 0 to        MaxSlicesPerPicture−1, inclusive, where MaxSlicesPerPicture is        specified in Annex A. When no_pic_partition_flag is equal to 1,        the value of num_slices_in_pic_minus1 is inferred to be equal to        0.        tile_idx_delta_present_flag equal to 0 specifies that        tile_idx_delta values are not present in the PPS and all        rectangular slices in pictures referring to the PPS are        specified in raster order according to the process defined in        clause 6.5.1. tile_idx_delta_present_flag equal to 1 specifies        that tile_idx_delta values may be present in the PPS and all        rectangular slices in pictures referring to the PPS are        specified in the order indicated by the values of        tile_idx_delta. When not present, the value of        tile_idx_delta_present_flag is inferred to be equal to 0.        slice_width_in_tiles_minus1[i] plus 1 specifies the width of the        i-th rectangular slice in units of tile columns. The value of        slice_width_in_tiles_minus1[i] shall be in the range of 0 to        NumTileColumns−1, inclusive. When slice_width_in_tiles_minus1[i]        is not present, the following applies:    -   If NumTileColumns is equal to 1, the value of        slice_width_in_tiles_minus1[i] is inferred to be equal to 0.    -   Otherwise, the value of slice_width_in_tiles_minus1[i] is        inferred as specified in clause 6.5.1.        slice_height_in_tiles_minus1[i] plus 1 specifies the height of        the i-th rectangular slice in units of tile rows. The value of        slice_height_in_tiles_minus1[i] shall be in the range of 0 to        NumTileRows−1, inclusive.        When slice_height_in_tiles_minus1[i] is not present, the        following applies:    -   If NumTileRows is equal to 1, or tile_idx_delta_present_flag is        equal to 0 and tileIdx % NumTileColumns is greater than 0), the        value of slice_height_in_tiles_minus1[i] is inferred to be equal        to 0.    -   Otherwise (NumTileRows is not equal to 1, and        tile_idx_delta_present_flag is equal to 1 or tileIdx %        NumTileColumns is equal to 0), when tile_idx_delta_present_flag        is equal to 1 or tileIdx % NumTileColumns is equal to 0, the        value of slice_height_in_tiles_minus1[i] is inferred to be equal        to slice_height_in_tiles_minus1[i−1].        num_exp_slices_in_tile[i] specifies the number of explicitly        provided slice heights in the current tile that contains more        than one rectangular slices. The value of        num_exp_slices_in_tile[i] shall be in the range of 0 to        RowHeight[tileY]−1, inclusive, where tileY is the tile row index        containing the i-th slice. When not present, the value of        num_exp_slices_in_tile[i] is inferred to be equal to 0. When        num_exp_slices_in_tile[i] is equal to 0, the value of the        variable NumSlicesInTile[i] is derived to be equal to 1.        exp_slice_height_in_ctus_minus1 [j] plus 1 specifies the height        of the j-th rectangular slice in the current tile in units of        CTU rows. The value of exp_slice_height_in_ctus_minus1[j] shall        be in the range of 0 to RowHeight[tileY]−1, inclusive, where        tileY is the tile row index of the current tile.        When num_exp_slices_in_tile[i] is greater than 0, the variable        NumSlicesInTile[i] and SliceHeightInCtusMinus1[i+k] for k in the        range of 0 to NumSlicesInTile[i]−1 are derived as follows:

remainingHeightInCtbsY = RowHeight[ SliceTopLeftTileIdx[ i ] /NumTileColumns ] numExpSliceInTile = num_exp_slices_in_tile[ i ] for( j= 0; j < numExpSliceInTile − 1; j++ ) {  SliceHeightInCtusMinus1[ i++ ]= exp_slice_height_in_ctu_minus1[ j ]  remainingHeightInCtbsY −=SliceHeightInCtusMinus1[ j ] } uniformSliceHeightMinus1 =SliceHeightInCtusMinus1[ i − 1 ] (81) while( remainingHeightInCtbsY >=(uniformSliceHeightMinus1 + 1) ) {  SliceHeightInCtusMinus1[ i++ ] =uniformSliceHeightMinus1  remainingHeightInCtbsY −=(uniformSliceHeightMinus1 + 1)  j++ } if( remainingHeightInCtbsY > 0 ) { SliceHeightInCtusMinus1[ i++ ] = remainingHeightInCtbsY  j++ }NumSlicesInTile[ i ] = jtile_idx_delta[i] specifies the difference between the tile index of thefirst tile in the i-th rectangular slice and the tile index of the firsttile in the (i+1)-th rectangular slice. The value of tile_idx_delta[i]shall be in the range of −NumTilesInPic+1 to NumTilesInPic−1, inclusive.When not present, the value of tile_idx_delta[i] is inferred to be equalto 0. When present, the value of tile_idx_delta[i] shall not be equal to0.loop_filter_across_tiles_enabled_flag equal to 1 specifies that in-loopfiltering operations may be performed across tile boundaries in picturesreferring to the PPS. loop_filter_across_tiles_enabled_flag equal to 0specifies that in-loop filtering operations are not performed acrosstile boundaries in pictures referring to the PPS. The in-loop filteringoperations include the deblocking filter, sample adaptive offset filter,and adaptive loop filter operations. When not present, the value ofloop_filter_across_tiles_enabled_flag is inferred to be equal to 1.loop_filter_across_slices_enabled_flag equal to 1 specifies that in-loopfiltering operations may be performed across slice boundaries inpictures referring to the PPS. loop_filter_across_slice_enabled_flagequal to 0 specifies that in-loop filtering operations are not performedacross slice boundaries in pictures referring to the PPS. The in-loopfiltering operations include the deblocking filter, sample adaptiveoffset filter, and adaptive loop filter operations. When not present,the value of loop_filter_across_slices_enabled_flag is inferred to beequal to 0.cabac_init_present_flag equal to 1 specifies that cabac_init_flag ispresent in slice headers referring to the PPS. cabac_init_present_flagequal to 0 specifies that cabac_init_flag is not present in sliceheaders referring to the PPS.num_ref_idx_default_active_minus1[i] plus 1, when i is equal to 0,specifies the inferred value of the variable NumRefIdxActive[0] for P orB slices with num_ref_idx_active_override_flag equal to 0, and, when iis equal to 1, specifies the inferred value of NumRefIdxActive[1] for Bslices with num_ref_idx_active_override_flag equal to 0. The value ofnum_ref_idx_default_active_minus1[i] shall be in the range of 0 to 14,inclusive.rpl1_idx_present_flag equal to 0 specifies that refpic_list_sps_flag[1]and refpic_list_idx[1] are not present in the PH syntax structures orthe slice headers for pictures referring to the PPS.rpl1_idx_present_flag equal to 1 specifies that ref_pic_list_sps_flag[1]and refpic_list_idx[1] may be present in the PH syntax structures or theslice headers for pictures referring to the PPS.init_qp_minus26 plus 26 specifies the initial value of SliceQp_(Y) foreach slice referring to the PPS. The initial value of SliceQp_(Y) ismodified at the picture level when a non-zero value of ph_qp_delta isdecoded or at the slice level when a non-zero value of slice_qp_delta isdecoded. The value of init_qp_minus26 shall be in the range of−(26+QpBdOffset) to +37, inclusive.cu_qp_delta_enabled_flag equal to 1 specifies that theph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slicesyntax elements are present in PHs referring to the PPS andcu_qp_delta_abs may be present in the transform unit syntax.cu_qp_delta_enabled_flag equal to 0 specifies that theph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slicesyntax elements are not present in PHs referring to the PPS andcu_qp_delta_abs is not present in the transform unit syntax.pps_chroma_tool_offsets_present_flag equal to 1 specifies that chromatool offsets related syntax elements are present in the PPS RBSP syntaxstructure. pps_chroma_tool_offsets_present_flag equal to 0 specifiesthat chroma tool offsets related syntax elements are not present in inthe PPS RBSP syntax structure. When ChromaArrayType is equal to 0, thevalue of pps_chroma_tool_offsets_present_flag shall be equal to 0.pps_cb_qp_offset and pps_cr_qp_offset specify the offsets to the lumaquantization parameter Qp′_(Y) used for deriving Qp′_(Cb) and Qp′_(Cr),respectively. The values of pps_cb_qp_offset and pps_cr_qp_offset shallbe in the range of −12 to +12, inclusive. When ChromaArrayType is equalto 0, pps_cb_qp_offset and pps_cr_qp_offset are not used in the decodingprocess and decoders shall ignore their value. When not present, thevalues of pps_cb_qp_offset and pps_cr_qp_offset are inferred to beequalt to 0.pps_joint_cbcr_qp_offset_present_flag equal to 1 specifies thatpps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] arepresent in the PPS RBSP syntax structure.pps_joint_cbcr_qp_offset_present_flag equal to 0 specifies thatpps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are notpresent in the PPS RBSP syntax structure. When ChromaArrayType is equalto 0 or sps_joint_cbcr_enabled_flag is equal to 0, the value ofpps_joint_cbcr_qp_offset_present_flag shall be equal to 0. When notpresent, the value of pps_joint_cbcr_qp_offset_present_flag is inferredto be equal to 0.pps_joint_cbr_qp_offset_value specifies the offset to the lumaquantization parameter Qp′_(Y) used for deriving Qp′_(CbCr). The valueof pps_joint_cbcr_qp_offset_value shall be in the range of −12 to +12,inclusive. When ChromaArrayType is equal to 0 orsps_joint_cbcr_enabled_flag is equal to 0,pps_joint_cbcr_qp_offset_value is not used in the decoding process anddecoders shall ignore its value. Whenpps_joint_cbcr_qp_offset_present_flag is equal to 0,pps_joint_cbcr_qp_offset_value is not present and is inferred to beequal to 0.pps_slice_chroma_qp_offsets_present_flag equal to 1 specifies that theslice_cb_qp_offset and slice_cr_qp_offset syntax elements are present inthe associated slice headers. pps_slice_chroma_qp_offsets_present_flagequal to 0 specifies that the slice_cb_qp_offset and slice_cr_qp_offsetsyntax elements are not present in the associated slice headers. Whennot present, the value of pps_slice_chroma_qp_offsets_present_flag isinferred to be equal to 0.pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 specifies that theph_cu_chroma_qp_offset_subdiv_intra_slice andph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present inPHs referring to the PPS and cu_chroma_qp_offset_flag may be present inthe transform unit syntax and the palette coding syntax.pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 specifies that theph_cu_chroma_qp_offset_subdiv_intra_slice andph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are notpresent in PHs referring to the PPS and the cu_chroma_qp_offset_flag isnot present in the transform unit syntax and the palette coding syntax.When not present, the value of pps_cu_chroma_qp_offset_list_enabled_flagis inferred to be equal to 0.chroma_qp_offset_list_len_minus1 plus 1 specifies the number ofcb_qp_offset_list[i], cr_qp_offset_list[i], andjoint_cbcr_qp_offset_list[i], syntax elements that are present in thePPS RBSP syntax structure. The value of chroma_qp_offset_list_len_minus1shall be in the range of 0 to 5, inclusive.cb_qp_offset_list[i], cr_qp_offset_list[i], andjoint_cbcr_qp_offset_list[i], specify offsets used in the derivation ofQp′_(Cb), Qp′_(Cr), and Qp′_(CbCr), respectively. The values ofcb_qp_offset_list[i], cr_qp_offset_list[i], andjoint_cbcr_qp_offset_list[i] shall be in the range of −12 to +12,inclusive. When pps_joint_cbcr_qp_offset_present_flag is equal to 0,joint_cbcr_qp_offset_list[i] is not present and it is inferred to beequal to 0.pps_weighted_pred_flag equal to 0 specifies that weighted prediction isnot applied to P slices referring to the PPS. pps_weighted_pred_flagequal to 1 specifies that weighted prediction is applied to P slicesreferring to the PPS. When sps_weighted_pred_flag is equal to 0, thevalue of pps_weighted_pred_flag shall be equal to 0.pps_weighted_bipred_flag equal to 0 specifies that explicit weightedprediction is not applied to B slices referring to the PPS.pps_weighted_bipred_flag equal to 1 specifies that explicit weightedprediction is applied to B slices referring to the PPS. Whensps_weighted_bipred_flag is equal to 0, the value ofpps_weighted_bipred_flag shall be equal to 0.deblocking_filter_control_present_flag equal to 1 specifies the presenceof deblocking filter control syntax elements in the PPS.deblocking_filter_control_present_flag equal to 0 specifies the absenceof deblocking filter control syntax elements in the PPS.deblocking_filter_override_enabled_flag equal to 1 specifies thepresence of ph_deblocking_filter_override_flag in the PHs referring tothe PPS or slice_deblocking_filter_override_flag in the slice headersreferring to the PPS. deblocking_filter_override_enabled_flag equal to 0specifies the absence of ph_deblocking_filter_override_flag in PHsreferring to the PPS or slice_deblocking_filter_override_flag in sliceheaders referring to the PPS. When not present, the value ofdeblocking_filter_override_enabled_flag is inferred to be equal to 0.pps_deblocking_filter_disabled_flag equal to 1 specifies that theoperation of deblocking filter is not applied for slices referring tothe PPS in which slice_deblocking_filter_disabled_flag is not present.pps_deblocking_filter_disabled_flag equal to 0 specifies that theoperation of the deblocking filter is applied for slices referring tothe PPS in which slice_deblocking_filter_disabled_flag is not present.When not present, the value of pps_deblocking_filter_disabled_flag isinferred to be equal to 0.pps_beta_offset_div2 and pps_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to the luma component for slices referring to the PPS, unlessthe default deblocking parameter offsets are overridden by thedeblocking parameter offsets present in the picture headers or the sliceheaders of the slices referring to the PPS. The values ofpps_beta_offset_div2 and pps_te_offset_div2 shall both be in the rangeof −12 to 12, inclusive. When not present, the values of pps_betaoffset_div2 and pps_tc_offset_div2 are both inferred to be equal to 0.pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to the Cb component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the picture headers or the slice headers ofthe slices referring to the PPS. The values of pps_cb_beta_offset_div2and pps_cb_te_offset_div2 shall both be in the range of −12 to 12,inclusive. When not present, the values of pps_cb_beta_offset_div2 andpps_cb_tc_offset_div2 are both inferred to be equal to 0.pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the defaultdeblocking parameter offsets for β and tC (divided by 2) that areapplied to the Cr component for slices referring to the PPS, unless thedefault deblocking parameter offsets are overridden by the deblockingparameter offsets present in the picture headers or the slice headers ofthe slices referring to the PPS. The values of pps_cr_beta_offset_div2and pps_cr_tc_offset_div2 shall both be in the range of −12 to 12,inclusive. When not present, the values of pps_cr beta offset_div2 andpps_cr_tc_offset_div2 are both inferred to be equal to 0.rpl_info_in_ph_flag equal to 1 specifies that reference picture listinformation is present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. rpl_info_in_ph_flag equal to 0 specifies that referencepicture list information is not present in the PH syntax structure andmay be present in slice headers referring to the PPS that do not containa PH syntax structure.dbf_info_in_ph_flag equal to 1 specifies that deblocking filterinformation is present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. dbf_info_in_ph_flag equal to 0 specifies that deblockingfilter information is not present in the PH syntax structure and may bepresent in slice headers referring to the PPS that do not contain a PHsyntax structure. When not present, the value of dbf_info_in_ph_flag isinferred to be equal to 0.sao_info_in_ph_flag equal to 1 specifies that SAO filter information ispresent in the PH syntax structure and not present in slice headersreferring to the PPS that do not contain a PH syntax structure.sao_info_in_ph_flag equal to 0 specifies that SAO filter information isnot present in the PH syntax structure and may be present in sliceheaders referring to the PPS that do not contain a PH syntax structure.alf_info_in_ph_flag equal to 1 specifies that ALF information is presentin the PH syntax structure and not present in slice headers referring tothe PPS that do not contain a PH syntax structure. alf_info_in_ph_flagequal to 0 specifies that ALF information is not present in the PHsyntax structure and may be present in slice headers referring to thePPS that do not contain a PH syntax structure.wp_info_in_ph_flag equal to 1 specifies that weighted predictioninformation may be present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. wp_info_in_ph_flag equal to 0 specifies that weightedprediction information is not present in the PH syntax structure and maybe present in slice headers referring to the PPS that do not contain aPH syntax structure. When not present, the value of wp_info_in_ph_flagis inferred to be equal to 0.qp_delta_info_in_ph_flag equal to 1 specifies that QP delta informationis present in the PH syntax structure and not present in slice headersreferring to the PPS that do not contain a PH syntax structure.qp_delta_info_in_ph_flag equal to 0 specifies that QP delta informationis not present in the PH syntax structure and may be present in sliceheaders referring to the PPS that do not contain a PH syntax structure.pps_ref_wraparound_enabled_flag equal to 1 specifies that horizontalwrap-around motion compensation is applied in inter prediction.pps_ref_wraparound_enabled_flag equal to 0 specifies that horizontalwrap-around motion compensation is not applied. When the value ofCtbSizeY/MinCbSizeY+1 is greater thanpic_width_in_luma_samples/MinCbSizeY−1, the value ofpps_ref_wraparound_enabled_flag shall be equal to 0. Whensps_ref_wraparound_enabled_flag is equal to 0, the value ofpps_ref_wraparound_enabled_flag shall be equal to 0.pps_ref_wraparound_offset plus (CtbSizeY/MinCbSizeY)+2 specifies theoffset used for computing the horizontal wrap-around position in unitsof MinCbSizeY luma samples. The value of pps_ref_wraparound_offset shallbe in the range of 0 to(pic_width_in_luma_samples/MinCbSizeY)−(CtbSizeY/MinCbSizeY)−2,inclusive. The variable PpsRefWraparoundOffset is set equal topps_ref_wraparound_offset+(CtbSizeY/MinCbSizeY)+2.picture_header_extension_present_flag equal to 0 specifies that no PHextension syntax elements are present in PHs referring to the PPS.picture_header_extension_present_flag equal to 1 specifies that PHextension syntax elements are present in PHs referring to the PPS.picture_header_extension_present_flag shall be equal to 0 in bitstreamsconforming to this version of this Specification.slice_header_extension_present_flag equal to 0 specifies that no sliceheader extension syntax elements are present in the slice headers forcoded pictures referring to the PPS. slice_header_extension_present_flagequal to 1 specifies that slice header extension syntax elements arepresent in the slice headers for coded pictures referring to the PPS.slice_header_extension_present_flag shall be equal to 0 in bitstreamsconforming to this version of this Specification.pps_extension_flag equal to 0 specifies that no pps_extension_data_flagsyntax elements are present in the PPS RBSP syntax structure.pps_extension_flag equal to 1 specifies that there arepps_extension_data_flag syntax elements present in the PPS RBSP syntaxstructure.pps_extension_data_flag may have any value. Its presence and value donot affect decoder conformance to profiles specified in this version ofthis Specification. Decoders conforming to this version of thisSpecification shall ignore all pps_extension_data_flag syntax elements.

3.2. APS Syntax and Semantics

In the latest VVC draft text, the APS syntax and semantics are asfollows:

Descriptor adaptation_parameter_set_rbsp( ) { adaptation_parameter_set_id u(5)  aps_params_type u(3)  if(aps_params_type = = ALF_APS )   alf_data( )  else if( aps_params_type == LMCS_APS )   lmcs_data( )  else if( aps_params_type = = SCALING_APS )  scaling_list_data( )  aps_extension_flag u(1)  if( aps_extension_flag)   while( more_rbsp_data( ) )    aps_extension_data_flag u(1) rbsp_trailing_bits( ) }

The APS RBSP contains a ALF syntax structure, i.e., alf data( ).

Descriptor alf_data( ) {  alf_luma_filter_signal_flag u(1) alf_chroma_filter_signal_flag u(1)  alf_cc_cb_filter_signal_flag u(1) alf_cc_cr_filter_signal_flag u(1)  if( alf_luma_filter_signal_flag ) {  alf_luma_clip_flag u(1)   alf_luma_num_filters_signalled_minus1 ue(v)  if( alf_luma_num_filters_signalled_minus1 > 0 )    for( filtIdx = 0;filtIdx < NumAlfFilters; filtIdx++ )     alf_luma_coeff_delta_idx[filtIdx ] u(v)   for( sfIdx = 0; sfIdx <=alf_luma_num_filters_signalled_minus1; sfIdx++ )    for( j = 0; j < 12;j++ ) {     alf_luma_coeff_abs[ sfIdx ][ j ] ue(v)     if(alf_luma_coeff_abs[ sfIdx ][ j ] )      alf_luma_coeff_sign[ sfIdx ][ j] u(1)    }   if( alf_luma_clip_flag )    for( sfIdx = 0; sfIdx <=alf_luma_num_filters_signalled_minus1; sfIdx++ )     for( j= 0; j < 12;j++ )      alf_luma_clip_idx[ sfIdx ][ j ] u(2)  }  if(alf_chroma_filter_signal_flag ) {   alf_chroma_clip_flag u(1)  alf_chroma_num_alt_filters_minus1 ue(v)   for( altIdx = 0; altIdx <=alf_chroma_num_alt_filters_minus1; altIdx++ ) {    for( j = 0; j < 6;j++ ) {     alf_chroma_coeff_abs[ altIdx ][ j ] ue(v)     if(alf_chroma_coeff_abs[ altIdx ][ j ] > 0 )      alf_chroma_coeff_sign[altIdx ][ j ] u(1)    }    if( alf_chroma_clip_flag )     for( j = 0; j< 6; j++ )      alf_chroma_clip_idx[ altIdx ][ j ] u(2)   }  }  if(alf_cc_cb_filter_signal_flag ) {   alf_cc_cb_filters_signalled_minus1ue(v)   for( k = 0; k < alf_cc_cb_filters_signalled_minus1 + 1; k++ ) {   for( j = 0; j < 7; j++ ) {     alf_cc_cb_mapped_coeff_abs[ k ][ j ]u(3)     if( alf_cc_cb_mapped_coeff_abs[ k ][ j ] )     alf_cc_cb_coeff_sign[ k ][ j ] u(1)    }   }  }  if(alf_cc_cr_filter_signal_flag ) {   alf_cc_cr_filters_signalled_minus1ue(v)   for( k = 0; k < alf_cc_cr_filters_signalled_minus1 + 1; k++ ) {   for( j = 0; j < 7; j++ ) {     alf_cc_cr_mapped_coeff_abs[ k ][ j ]u(3)     if( alf_cc_cr_mapped_coeff_abs[ k ][ j ] )     alf_cc_cr_coeff_sign[ k ][ j ] u(1)    }   }  } }

The APS RBSP contains a LMCS syntax structure, i.e., lmcs_data( ).

Descriptor lmcs_data( ) {  lmcs_min_bin_idx ue(v) lmcs_delta_max_bin_idx ue(v)  lmcs_delta_cw_prec_minus1 ue(v)  for( i =lmcs_min_bin_idx; i <= LmcsMaxBinIdx; i++ ) {   lmcs_delta_abs_cw[ i ]u(v)   if( lmcs_delta_abs_cw[ i ] > 0 )    lmcs_delta_sign_cw_flag[ i ]u(1)  }  lmcs_delta_abs_crs u(3)  if( lmcs_delta_abs_crs > 0 )  lmcs_delta_sign_crs_flag u(1) }

The APS RBSP contains a scaling list data syntax structure, i.e.,scaling_list_data( ).

Descriptor scaling_list_data( ) { scaling_matrix_for_lfnst_disabled_flag u(1) scaling_list_chroma_present_flag u(1)  for( id = 0; id < 28; id ++ )  matrixSize = (id < 2) ? 2 : ( ( id < 8 ) ? 4 : 8 )   if(scaling_list_chroma_present_flag | | ( id % 3 = = 2) | | ( id = = 27) ){    scaling_list_copy_mode_flag[ id ] u(1)    if(!scaling_list_copy_mode_flag[ id ] )      scaling_list_pred_mode_flag[id ] u(1)    if( ( scaling_list_copy_mode_flag[ id ] | |scaling_list_pred_mode_flag[ id ] ) &&       id != 0 && id != 2 && id !=8 )      scaling_list_pred_id_delta[ id ] ue(v)     if(!scaling_list_copy_mode_flag[ id ] ) {      nextCoef = 0      if( id >13 ) {       scaling_list_dc_coef[ id − 14 ] se(v)       nextCoef +=scaling_list_dc_coef[ id − 14 ]      }      for( i = 0; i < matrixSize *matrixSize; i++ ) {       x = DiagScanOrder[ 3 ][ 3 ][ i ][ 0 ]       y= DiagScanOrder[ 3 ][ 3 ][ i ][ 1 ]       if( !( id > 25 && x >= 4 &&y >= 4 ) ) {        scaling_list_delta_coef[ id ][ i ] se(v)       nextCoef += scaling_list_delta_coef[ id ][ i ]       }      ScalingList[ id ][ i ] = nextCoef      }     }    }   }  }Each APS RBSP shall be available to the decoding process prior to itbeing referenced, included in at least one AU with TemporalId less thanor equal to the TemporalId of the coded slice NAL unit that refers it orprovided through external means.All APS NAL units with a particular value of adaptation_parameter_set_idand a particular value of aps_params_type within a PU, regardless ofwhether they are prefix or suffix APS NAL units, shall have the samecontent.adaptation_parameter_set_id provides an identifier for the APS forreference by other syntax elements.When aps_params_type is equal to ALF_APS or SCALING_APS, the value ofadaptation_parameter_set_id shall be in the range of 0 to 7, inclusive.When aps_params_type is equal to LMCS_APS, the value ofadaptation_parameter_set_id shall be in the range of 0 to 3, inclusive.Let apsLayerId be the value of the nuh_layer_id of a particular APS NALunit, and vclLayerId be the value of the nuh_layer_id of a particularVCL NAL unit. The particular VCL NAL unit shall not refer to theparticular APS NAL unit unless apsLayerId is less than or equal tovclLayerId and the layer with nuh_layer_id equal to apsLayerId isincluded in at least one OLS that includes the layer with nuh_layer_idequal to vclLayerId.aps_params_type specifies the type of APS parameters carried in the APSas specified in Table 6.

TABLE 6 APS parameters type codes and types of APS parameters Name ofType of APS aps_params_type aps_params_type parameters 0 ALF_APS ALFparameters 1 LMCS_APS LMCS parameters 2 SCALING_APS Scaling listparameters 3 . . . 7 Reserved ReservedAll APS NAL units with a particular value of aps_params_type, regardlessof the nuh_layer_id values, share the same value space foradaptation_parameter_set_id. APS NAL units with different values ofaps_params_type use separate values spaces foradaptation_parameter_set_id.

-   -   NOTE 1—An APS NAL unit (with a particular value of        adaptation_parameter_set_id and a particular value of        aps_params_type) can be shared across pictures, and different        slices within a picture can refer to different ALF APSs.    -   NOTE 2—A suffix APS NAL unit associated with a particular VCL        NAL unit (this VCL NAL unit precedes the suffix APS NAL unit in        decoding order) is not for use by the particular VCL NAL unit,        but for use by VCL NAL units following the suffix APS NAL unit        in decoding order.        aps_extension_flag equal to 0 specifies that no        aps_extension_data_flag syntax elements are present in the APS        RBSP syntax structure. aps_extension_flag equal to 1 specifies        that there are aps_extension_data_flag syntax elements present        in the APS RBSP syntax structure.        aps_extension_data_flag may have any value. Its presence and        value do not affect decoder conformance to profiles specified in        this version of this Specification. Decoders conforming to this        version of this Specification shall ignore all        aps_extension_data_flag syntax elements.        alf_luma_filter_signal_flag equal to 1 specifies that a luma        filter set is signalled. alf_luma_filter_signal_flag equal to 0        specifies that a luma filter set is not signalled.        alf_chroma_filter_signal_flag equal to 1 specifies that a chroma        filter is signalled. alf_chroma_filter_signal_flag equal to 0        specifies that a chroma filter is not signalled. When        ChromaArrayType is equal to 0, alf_chroma_filter_signal_flag        shall be equal to 0.        At least one of the values of alf_luma_filter_signal_flag,        alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag and        alf_cc_cr_filter_signal_flag shall be equal to 1.        The variable NumAlfFilters specifying the number of different        adaptive loop filters is set equal to 25.        alf_luma_clip_flag equal to 0 specifies that linear adaptive        loop filtering is applied on luma component. alf_luma_clip_flag        equal to 1 specifies that non-linear adaptive loop filtering may        be applied on luma component.        alf_luma_num_filters_signalled_minus1 plus 1 specifies the        number of adaptive loop filter classes for which luma        coefficients can be signalled. The value of        alf_luma_num_filters_signalled_minus1 shall be in the range of 0        to NumAlfFilters−1, inclusive.        alf_luma_coeff_delta_idx[filtIdx] specifies the indices of the        signalled adaptive loop filter luma coefficient deltas for the        filter class indicated by filtIdx ranging from 0 to        NumAlfFilters−1. When        alf_luma_coeff_delta_idx[filtIdx] is not present, it is inferred        to be equal to 0. The length of        alf_luma_coeff_delta_idx[filtIdx] is Ceil(Log        2(alf_luma_num_filters_signalled_minus1+1)) bits. The value of        alf_luma_coeff_delta_idx[filtIdx] shall be in the range of 0 to        alf_luma_num_filters_signalled_minus1, inclusive.        alf_luma_coeff_abs[sfIdx][j] specifies the absolute value of the        j-th coefficient of the signalled luma filter indicated by        sfIdx. When alf_luma_coeff_abs[sfIdx][j] is not present, it is        inferred to be equal 0. The value of        alf_luma_coeff_abs[sfIdx][j] shall be in the range of 0 to 128,        inclusive.        alf_luma_coeff_sign[sfIdx][j] specifies the sign of the j-th        luma coefficient of the filter indicated by sfIdx as follows:    -   If alf_luma_coeff_sign[sfIdx][j] is equal to 0, the        corresponding luma filter coefficient has a positive value.    -   Otherwise (alf_luma_coeff_sign[sfIdx][j] is equal to 1), the        corresponding luma filter coefficient has a negative value.        When alf_luma_coeff_sign[sfIdx][j] is not present, it is        inferred to be equal to 0.        The variable filtCoeff[sfIdx][j] with sfIdx=0 . . .        alf_luma_num_filters_signalled_minus1, j=0 . . . 11 is        initialized as follows:

filtCoeff[sfIdx][j]=alf_luma_coeff_abs[sfIdx][j]*(1−2*alf_luma_coeff_sign[sfIdx][j])  (93)

The luma filter coefficients AlfCoeff_(L)[adaptation_parameter_set_id]with elementsAlfCoeff_(L)[adaptation_parameter_set_id][filtIdx][j], with filtIdx=0 .. . NumAlfFilters−1 and j=0 . . . 11 are derived as follows:

AlfCoeff_(L)[adaptation_parameter_set_id][filtIdx][j]=filtCoeff[alf_luma_coeff_delta_idx[filtIdx]][j]  (94)

The fixed filter coefficients AlfFixFiltCoeff[i][j] with i=0 . . . 64,j=0 . . . 11 and the class to filter mapping AlfClassToFiltMap[m][n]with m=0 . . . 15 and n=0.24 are derived as follows:

AlfFixFiltCoeff = (95)  {   { 0, 0, 2, −3, 1, −4, 1, 7, −1, 1, −1, 5}  { 0, 0, 0, 0, 0, −1, 0, 1, 0, 0, −1, 2}   { 0, 0, 0, 0, 0, 0, 0, 1, 0,0, 0, 0}   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, −1, 1}   { 2, 2, −7, −3, 0,−5, 13, 22, 12, −3, −3, 17}   {−1, 0, 6, −8, 1, −5, 1, 23, 0, 2, −5, 10}  { 0, 0, −1, −1, 0, −1, 2, 1, 0, 0, −1, 4}   { 0, 0, 3, −11, 1, 0, −1,35, 5, 2, −9, 9}   { 0, 0, 8, −8, −2, −7, 4, 4, 2, 1, −1, 25}   { 0, 0,1, −1, 0, −3, 1, 3, −1, 1, −1, 3}   { 0, 0, 3, −3, 0, −6, 5, −1, 2, 1,−4, 21}   {−7, 1, 5, 4, −3, 5, 11 13 12, −8, 11, 12}   {−5, −3, 6, −2,−3, 8, 14, 15, 2, −7, 11, 16}   { 2, −1, −6, −5, −2, −2, 20, 14, −4, 0,−3, 25}   { 3, 1, −8, −4, 0, −8, 22 5, −3, 2, −10, 29}   { 2, 1, −7, −1,2, −11, 23, −5, 0, 2, −10, 29}   {−6, −3, 8, 9, −4, 8, 9, 7, 14, −2, 8,9}   { 2, 1, −4, −7, 0, −8, 17, 22, 1, −1, −4, 23}   { 3, 0, −5, −7, 0,−7, 15, 18, −5, 0, −5, 27}   { 2, 0, 0, −7, 1, −10, 13, 13, −4, 2, −7,24}   { 3, 3, −13, 4, −2, −5, 9, 21, 25, −2, −3, 12}   {−5, −2, 7, −3,−7, 9, 8, 9, 16, −2, 15, 12}   { 0, −1, 0, −7, −5, 4, 11, 11, 8, −6, 12,21}   { 3, −2, −3, −8, −4, −1, 16, 15, −2, −3, 3, 26}   { 2, 1, −5, −4,−1, −8, 16, 4, −2, 1, −7, 33}   { 2, 1, −4, −2, 1, −10, 17, −2, 0, 2,−11, 33}   { 1, −2, 7, −15, −16, 10, 8, 8, 20, 11, 14, 11}   { 2, 2, 3,−13, −13, 4, 8, 12, 2, −3, 16, 24}   { 1, 4, 0, −7, −8, −4, 9, 9, −2,−2, 8, 29}   { 1, 1, 2, −4, −1, −6, 6, 3, −1, −1, −3, 30}   {−7, 3, 2,10, −2, 3, 7, 11, 19, −7, 8, 10}   { 0, −2, −5, −3, −2, 4, 20, 15, −1,−3, −1, 22}   { 3, −1, −8, −4, −1, −4, 22, 8, −4, 2, −8, 28}   { 0, 3,−14, 3, 0, 1, 19, 17, 8, −3, −7, 20}   { 0, 2, −1, −8, 3, −6, 5, 21, 1,1, −9, 13}   {−4, −2, 8, 20, −2, 2, 3, 5, 21, 4, 6, 1}   { 2, −2, −3,−9, −4, 2, 14, 16, 3, −6, 8, 24}   { 2, 1, 5, −16, −7, 2, 3, 11, 15, −3,11, 22}   { 1, 2, 3, −11, −2, −5, 4, 8, 9, −3, −2, 26}   { 0, −1, 10,−9, −1, −8, 2, 3, 4, 0, 0, 29}   { 1, 2, 0, −5, 1, −9, 9, 3, 0, 1, −7,20}   {−2, 8, −6, −4, 3, −9, −8, 45, 14, 2, −13, 7}   { 1, −1, 16, −19,−8, −4, −3, 2, 19, 0, 4, 30}   { 1, 1, −3, 0, 2, −11, 15, −5, 1, 2, −9,24}   { 0, 1, −2, 0, 1, −4, 4, 0, 0, 1, −4, 7}   { 0, 1, 2, −5, 1, −6,4, 10, −2, 1, −4, 10}   { 3, 0, −3, −6, −2, −6, 14, 8, −1, −1, −3, 31}  { 0, 1, 0, −2, 1, −6, 5, 1, 0, 1, −5, 13}   { 3, 1, 9, −19, −21, 9, 7,6, 13, 5, 15, 21}   { 2, 4, 3, −12, −13, 1, 7, 8, 3, 0, 12, 26}   { 3,1, −8, −2, 0, −6, 18, 2, −2, 3, −10, 23}   { 1, 1, −4, −1, 1, −5, 8, 1,−1, 2, −5, 10}   { 0, 1, −1, 0, 0, −2, 2, 0, 0, 1, −2, 3}   { 1, 1, −2,−7, 1, −7, 14, 18, 0, 0, −7, 21}   { 0, 1, 0, −2, 0, −7, 8, 1, −2, 0,−3, 24}   { 0, 1, 1, −2, 2, −10, 10, 0, −2, 1, −7, 23}   { 0, 2, 2, −11,2, −4, −3, 39, 7, 1, −10, 9}   { 1, 0, 13, −16, −5, −6, −1, 8, 6, 0, 6,29}   { 1, 3, 1, −6, −4, −7, 9, 6, −3, −2, 3, 33}   { 4, 0, −17, −1, −1,5, 26, 8, −2, 3, −15, 30}   { 0, 1, −2, 0, 2, −8, 12, −6, 1, 1, −6, 16}  { 0, 0, 0, −1, 1, −4, 4, 0, 0, 0, −3, 11}   { 0, 1, 2, −8, 2, −6, 5,15, 0, 2, −7, 9}   { 1, −1, 12, −15, −7, −2, 3, 6, 6, −1, 7, 30}  },AlfClassToFiltMap = (96)  {   { 8, 2, 2, 2, 3, 4, 53, 9, 9, 52, 4, 4, 5,9, 2, 8, 10, 9, 1, 3, 39, 39, 10, 9,  52 }   { 11, 12, 13, 14, 15, 30,11, 17, 18, 19, 16, 20, 20, 4, 53, 21, 22, 23, 14, 25, 26, 26, 27, 28, 10 }   { 16, 12, 31, 32, 14, 16, 30, 33, 53, 34, 35, 16, 20, 4, 7, 16,21, 36, 18, 19, 21, 26, 37, 38,  39 }   { 35, 11, 13, 14, 43, 35, 16, 4,34, 62, 35, 35, 30, 56, 7, 35, 21, 38, 24, 40, 16, 21, 48, 57,  39 }   {11, 31, 32, 43, 44, 16, 4, 17, 34, 45, 30, 20, 20, 7, 5, 21, 22, 46, 40,47, 26, 48, 63, 58,  10 }   { 12, 13, 50, 51, 52, 11, 17, 53, 45, 9, 30,4, 53, 19, 0, 22, 23, 25, 43, 44, 37, 27, 28, 10,  55 }   { 30, 33, 62,51, 44, 20, 41, 56, 34, 45, 20, 41, 41, 56, 5, 30, 56, 38, 40, 47, 11,37, 42, 57,  8 }   { 35, 11, 23, 32, 14, 35, 20, 4, 17, 18, 21, 20, 20,20, 4, 16, 21, 36, 46, 25, 41, 26, 48, 49,  58 }   { 12, 31, 59, 59, 3,33, 33, 59, 59, 52, 4, 33, 17, 59, 55, 22, 36, 59, 59, 60, 22, 36, 59,25,  55 }   { 31, 25, 15, 60, 60, 22, 17, 19, 55, 55, 20, 20, 53, 19,55, 22, 46, 25, 43, 60, 37, 28, 10, 55,  52 }   { 12, 31, 32, 50, 51,11, 33, 53, 19, 45, 16, 4, 4, 53, 5, 22, 36, 18, 25, 43, 26, 27, 27, 28, 10 }   { 5, 2, 44, 52, 3, 4, 53, 45, 9, 3, 4, 56, 5, 0, 2, 5, 10, 47,52, 3, 63, 39, 10, 9,  52 }   { 12, 34, 44, 44, 3, 56, 56, 62, 45, 9,56, 56, 7, 5, 0, 22, 38, 40, 47, 52, 48, 57, 39, 10,  9 }   { 35, 11,23, 14, 51, 35, 20, 41, 56, 62, 16, 20, 41, 56, 7, 16, 21, 38, 24, 40,26, 26, 42, 57,  39 }   { 33, 34, 51, 51, 52, 41, 41, 34, 62, 0, 41, 41,56, 7, 5, 56, 38, 38, 40, 44, 37, 42, 57, 39,  10 }   { 16, 31, 32, 15,60, 30, 4, 17, 19, 25, 22, 20, 4, 53, 19, 21, 22, 46, 25, 55, 26, 48,63, 58,  55 }  {,It is a requirement of bitstream conformance that the values ofAlfCoeff_(L)[adaptation_parameterset_d][filtIdx][j] with filtIdx=0 . . .NumAlfFilters−1, j=0 . . . 11 shall be in the range of −2⁷ to 2⁷−1,inclusive.alf_luma_clip_dx[sfIdx][j] specifies the clipping index of the clippingvalue to use before multiplying by the j-th coefficient of the signalledluma filter indicated by sfIdx. It is a requirement of bitstreamconformance that the values of alf_luma_clip_idx[sfIdx][j] with sfIdx=0. . . alf_luma_num_filters_signalled_minus1 and j=0 . . . 11 shall be inthe range of 0 to 3, inclusive.The luma filter clipping values AlfClip_(L)[adaptation_parameter_set_id]with elementsAlfClip_(L)[adaptation_parameter_set_id][filtIdx][j], with filtIdx=0 . .. NumAlfFilters−1 and j=0 . . . 11 are derived as specified in Table 8depending on BitDepth and clipIdx set equal toalf_luma_clip_idx[alf_luma_coeff_delta_idx[filtIdx] ][j].alf_chroma_clip_flag equal to 0 specifies that linear adaptive loopfiltering is applied on chroma components; alf_chroma_clip_flag equal to1 specifies that non-linear adaptive loop filtering is applied on chromacomponents. When not present, alf_chroma_clip_flag is inferred to beequal to 0.alf_chroma_num_alt_filters_minus1 plus 1 specifies the number ofalternative filters for chroma components. The value ofalf_chroma_num_alt_filters_minus1 shall be in the range of 0 to 7,inclusive.alf_chroma_coeff_abs[altIdx][j] specifies the absolute value of the j-thchroma filter coefficient for the alternative chroma filter with indexaltIdx. When alf_chroma_coeff_abs[altIdx][j] is not present, it isinferred to be equal 0. The value of alf_chroma_coeff_abs[sfIdx][j]shall be in the range of 0 to 128, inclusive.alf_chroma_coeff_sign[altIdx][j] specifies the sign of the j-th chromafilter coefficient for the alternative chroma filter with index altIdxas follows:

-   -   If alf_chroma_coeff_sign[altIdx][j] is equal to 0, the        corresponding chroma filter coefficient has a positive value.    -   Otherwise (alf_chroma_coeff_sign[altIdx][j] is equal to 1), the        corresponding chroma filter coefficient has a negative value.        When alf_chroma_coeff_sign[altIdx][j] is not present, it is        inferred to be equal to 0.        The chroma filter coefficients        AlfCoeff_(C)[adaptation_parameter_set_id][altIdx] with elements        AlfCoeff_(C)[adaptation_parameter_set_id][altIdx][j], with        altIdx=0 . . . alf_chroma_num_alt_filters_minus1, j=0 . . . 5        are derived as follows:

AlfCoeff_(C)[adaptation_parameter_set_id][altIdx][j]=alf_chroma_coeff_abs[altIdx][j]*(1−2*alf_chroma_coeff_sign[altIdx][j])  (97)

It is a requirement of bitstream conformance that the values ofAlfCoeff_(C)[adaptation_parameter_set_id][altIdx][j] with altIdx=0 . . .alf_chroma_num_alt_filters_minus1, j=0 . . . 5 shall be in the range of−2⁷ to 2⁷−1, inclusive.alf_cc_cb_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cb colour component are signalled.alf_cc_cb_filter_signal_flag equal to 0 specifies that cross-componentfilters for Cb colour component are not signalled. When ChromaArrayTypeis equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0.alf_cc_cb_filters_signalled_minus1 plus 1 specifies the number ofcross-component filters for the Cb colour component signalled in thecurrent ALF APS. The value of alf_cc_cb_filters_signalled_minus1 shallbe in the range of 0 to 3, inclusive.alf_cc_cb_mapped_coeff_abs[k][j] specifies the absolute value of thej-th mapped coefficient of the signalled k-th cross-component filter forthe Cb colour component. When alf_cc_cb_mapped_coeff_abs[k][j] is notpresent, it is inferred to be equal to 0.alf_cc_cb_coeff_sign[k][j] specifies the sign of the j-th coefficient ofthe signalled k-th cross-component filter for the Cb colour component asfollows:

-   -   If alf_cc_cb_coeff_sign[k][j] is equal to 0, the corresponding        cross-component filter coefficient has a positive value.    -   Otherwise (alf_cc_cb_sign[k][j] is equal to 1), the        corresponding cross-component filter coefficient has a negative        value.        When alf_cc_cb_coeff_sign[k][j] is not present, it is inferred        to be equal to 0.        The signalled k-th cross-component filter coefficients for the        Cb colour component        CcAlfApsCoeff_(Cb)[adaptation_parameter_set_id][k][j], with j=0        . . . 6 are derived as follows:    -   If alf_cc_cb_mapped_coeff_abs[k][j] is equal to 0,        CcAlfApsCoeff_(Cb)[adaptation_parameter_set_id][k][j] is set        equal to 0.    -   Otherwise, CcAlfApsCoeff_(Cb)[adaptation_parameter_set_id][k][j]        is set equal to        (1−2*alf_cc_cb_coeff_sign[k][j])*2^(alf_cc_cb_mapped_coeff_abs[k][j]−1).        alf_cc_cr_filter_signal_flag equal to 1 specifies that        cross-component filters for the Cr colour component are        signalled. alf_cc_cr_filter_signal_flag equal to 0 specifies        that cross-component filters for the Cr colour component are not        signalled. When ChromaArrayType is equal to 0,        alf_cc_cr_filter_signal_flag shall be equal to 0.        alf_cc_cr_filters_signalled_minus1 plus 1 specifies the number        of cross-component filters for the Cr colour component signalled        in the current ALF APS. The value of        alf_cc_cr_filters_signalled_minus1 shall be in the range of 0 to        3, inclusive.        alf_cc_cr_mapped coeff_abs[k][j] specifies the absolute value of        the j-th mapped coefficient of the signalled k-th        cross-component filter for the Cr colour component. When        alf_cc_cr_mapped coeff_abs[k][j] is not present, it is inferred        to be equal to 0.        alf_cc_cr_coeff_sign[k][j] specifies the sign of the j-th        coefficient of the signalled k-th cross-component filter for the        Cr colour component as follows:    -   If alf_cc_cr_coeff_sign[k][j] is equal to 0, the corresponding        cross-component filter coefficient has a positive value.    -   Otherwise (alf_cc_cr_sign[k][j] is equal to 1), the        corresponding cross-component filter coefficient has a negative        value.        When alf_cc_cr_coeff_sign[k][j] is not present, it is inferred        to be equal to 0.        The signalled k-th cross-component filter coefficients for the        Cr colour component        CcAlfApsCoeff_(Cr)[adaptation_parameter_set_id][k][j], with j=0        . . . 6 are derived as follows:    -   If alf_cc_cr_mapped_coeff_abs[k][j] is equal to 0,        CcAlfApsCoeff_(Cr)[adaptation_parameter_set_id][k][j] is set        equal to 0.    -   Otherwise, CcAlfApsCoeff_(Cr)[adaptation_parameter_set_id][k][j]        is set equal to        (1-2*alf_cc_cr_coeff_sign[k][j])*2^(alf_cc_cr_mapped_coeff-abs[k][j]−1).        alf_chroma_clip_idx[altIdx][j] specifies the clipping index of        the clipping value to use before multiplying by the j-th        coefficient of the alternative chroma filter with index altIdx.        It is a requirement of bitstream conformance that the values of        alf_chroma_clip_idx[altIdx][j] with altIdx=0 . . .        alf_chroma_num_alt_filters_minus1, j=0 . . . 5 shall be in the        range of 0 to 3, inclusive.        The chroma filter clipping values        AlfClip_(C)[adaptation_parameter_set_id][altIdx] with elements        AlfClip_(C)[adaptation_parameter_set_id][altIdx][j], with        altIdx=0 . . . alf_chroma_num_alt_filters_minus1, j=0 . . . 5        are derived as specified in Table 8 depending on BitDepth and        clipIdx set equal to alf_chroma_clip_idx[altIdx][j].

TABLE 8 Specification AlfClip depending on BitDepth and clipIdx clipIdxBitDepth 0 1 2 3 8 28 25 23 21 9 29 26 24 22 10 210 27 25 23 11 211 2826 24 12 212 29 27 25 13 213 210 28 26 14 214 211 29 27 15 215 212 21028 16 216 213 211 29lmes_min_bin_idx specifies the minimum bin index used in the lumamapping with chroma scaling construction process. The value oflmcs_min_bin_idx shall be in the range of 0 to 15, inclusive.lmes_delta_max_bin_idx specifies the delta value between 15 and themaximum bin index LmcsMaxBinIdx used in the luma mapping with chromascaling construction process. The value of lmcs_delta_max_bin_idx shallbe in the range of 0 to 15, inclusive. The value of LmcsMaxBinIdx is setequal to 15−lmcs_delta_max_bin_idx. The value of LmcsMaxBinIdx shall begreater than or equal to lmcs_min_bin_idx.lmes_delta_cw_prec_minus1 plus 1 specifies the number of bits used forthe representation of the syntax lmcs_delta_abs_cw[i]. The value oflmcs_delta_cw_prec_minus1 shall be in the range of 0 to BitDepth−2,inclusive.lmes_delta_abs_cw[i] specifies the absolute delta codeword value for theith bin.lmes_delta_sign_cw_flag[i] specifies the sign of the variablelmcsDeltaCW[i] as follows:

-   -   If lmcs_delta_sign_cw_flag[i] is equal to 0, lmcsDeltaCW[i] is a        positive value.    -   Otherwise (lmcs_delta_sign_cw_flag[i] is not equal to 0),        lmcsDeltaCW[i] is a negative value.        When lmcs_delta_sign_cw_flag[i] is not present, it is inferred        to be equal to 0.        The variable OrgCW is derived as follows:

OrgCW=(1<<BitDepth)/16  (98)

The variable lmcsDeltaCW[i], with i=lmcs_min_bin_idx . . .LmcsMaxBinIdx, is derived as follows:

lmcsDeltaCW[i]=(1−2*lmcs_delta_sign_cw_flag[i])*lmcsdelta_abs_cw[i]  (99)

The variable lmcsCW[i] is derived as follows:

-   -   For i=0 . . . lmcs_min_bin_idx−1, lmcsCW[i] is set equal 0.    -   For i=lmcs_minbin_idx . . . LmcsMaxBinIdx, the following        applies:

lmcsCW[i]=OrgCW+lmcsDeltaCW[i]  (100)

-   -   The value of lmcsCW[i] shall be in the range of (OrgCW>>3) to        (OrgCW<<3−1), inclusive.    -   For i=LmcsMaxBinIdx+1.15, lmcsCW[i] is set equal 0.        It is a requirement of bitstream conformance that the following        condition is true:

Σ_(i=0) ¹⁵lmcsCW[i]<=(1<<BitDepth)−1  (101)

The variable InputPivot[i], with i=0 . . . 16, is derived as follows:

InputPivot[i]=i*OrgCW  (102)

The variable LmcsPivot[i] with i=0 . . . 16, the variables ScaleCoeff[i]and InvScaleCoeff[i] with i=0 . . . 15, are derived as follows:

LmcsPivot[ 0 ] = 0; for( i = 0; i <= 15; i++ ) {  LmcsPivot[ i + 1 ] =LmcsPivot[ i ] + lmcsCW[ i ]  ScaleCoeff[ i ] = ( lmcsCW[ i ] * (1 << 11) + ( 1 << ( Log2( OrgCW ) − 1 ) ) ) >> ( Log2( OrgCW ) )  if( lmcsCW[ i] == 0 ) (103)   InvScaleCoeff[ i ] = 0  else   InvScaleCoeff[ i ] =OrgCW * ( 1 << 11 ) / lmcsCW[ i ] }It is a requirement of bitstream conformance that, fori=Imcs_min_bin_idx . . . LmcsMaxBinIdx, when the value of LmcsPivot[i]is not a multiple of 1<<(BitDepth−5), the value of(LmcsPivot[i]>>(BitDepth−5)) shall not be equal to the value of(LmcsPivot[i+1]>>(BitDepth−5)).lmes_delta_abs_crs specifies the absolute codeword value of the variablelmcsDeltaCrs. The value of lmcs_delta_abs_crs shall be in the range of 0and 7, inclusive. When not present, lmcs_delta_abs_crs is inferred to beequal to 0.lmes_delta_sign_crs_flag specifies the sign of the variablelmcsDeltaCrs. When not present, lmcs_delta_sign_crs_flag is inferred tobe equal to 0.The variable lmcsDeltaCrs is derived as follows:

lmcsDeltaCrs=(1−2*lmcs_delta_sign_crs_flag)*lmcs_delta_abs_crs  (104)

It is a requirement of bitstream conformance that, when lmcsCW[i] is notequal to 0, (lmcsCW[i]+lmcsDeltaCrs) shall be in the range of (OrgCW>>3)to ((OrgCW<<3)−1), inclusive.The variable ChromaScaleCoeff[i], with i=0 . . . 15, is derived asfollows:

if( lmcsCW[ i ] = = 0 )  ChromaScaleCoeff[ i ] = ( 1 << 11 ) else ChromaScaleCoeff[ i ] = OrgCW * ( 1 << 11 ) / ( lmcsCW[ i ] +lmcsDeltaCrs )scaling_matrix_for_lfnst_disabled_flag equal to 1 specifies that scalingmatrices are not applied to blocks coded with LFNST.scaling_matrix_for_lfnst_disabled_flag equal to 0 specifies that thescaling matrices may apply to the blocks coded with LFNST.scaling_list_chroma_present_flag equal to 1 specifies that chromascaling lists are present in scaling_list_data( ).scaling_list_chroma_present_flag equal to 0 specifies that chromascaling lists are not present in scaling_list_data( ). It is arequirement of bitstream conformance thatscaling_list_chroma_present_flag shall be equal to 0 whenChromaArrayType is equal to 0, and shall be equal to 1 whenChromaArrayType is not equal to 0.scaling_list_copy_mode_flag[id] equal to 1 specifies that the values ofthe scaling list are the same as the values of a reference scaling list.The reference scaling list is specified byscaling_list_pred_id_delta[id]. scaling_list_copy_mode_flag[id] equal to0 specifies that scaling_list_pred_mode_flag is present.scaling_list_pred_mode_flag[id] equal to 1 specifies that the values ofthe scaling list can be predicted from a reference scaling list. Thereference scaling list is specified by scaling_list_pred_id_delta[id].scaling_list_pred_mode_flag[id] equal to 0 specifies that the values ofthe scaling list are explicitly signalled. When not present, the valueof scaling_list_pred_mode_flag[id] is inferred to be equal to 0.scaling_list_pred_id_delta[id] specifies the reference scaling list usedto derive the predicted scaling matrix ScalingMatrixPred[id]. When notpresent, the value of scaling_list_pred_id_delta[id] is inferred to beequal to 0. The value of scaling_list_pred_id_delta[id] shall be in therange of 0 to maxIdDelta with maxIdDelta derived depending on id asfollows:

maxIdDelta=(id<2)?id:((id<8)?(id−2):(id−8))  (106)

The variables refId and matrixSize are derived as follows:

refId=id−scaling_list_pred_id_delta[id]  (107)

matrixSize=(id<2)?2:((id<8)?4:8)  (108)

The (matrixSize)×(matrixSize) array ScalingMatrixPred[x][y] with x=0 . .. matrixSize−1, y=0 . . . matrixSize−1 and the variableScalingMatrixDCPred are derived as follows:

-   -   When both scaling_list_copy_mode_flag[id] and        scaling_list_pred_mode_flag[id] are equal to 0, all elements of        ScalingMatrixPred are set equal to 8, and the value of        ScalingMatrixDCPred is set equal to 8.    -   Otherwise, when scaling_list_pred_id_delta[id] is equal to 0,        all elements of ScalingMatrixPred are set equal to 16, and        ScalingMatrixDCPred is set equal to 16.    -   Otherwise (either scaling_list_copy_mode_flag[id] or        scaling_list_pred_mode_flag[id] is equal to 1 and        scaling_list_pred_id_delta[id] is greater than 0),        ScalingMatrixPred is set equal to ScalingMatrixRec[refId], and        the following applies for ScalingMatrixDCPred:        -   If refId is greater than 13, ScalingMatrixDCPred is set            equal to ScalingMatrixDCRec[refId−14].        -   Otherwise (refId is less than or equal to 13),            ScalingMatrixDCPred is set equal to ScalingMatrixPred[0][0].            scaling_list_dc_coef[id−14] is used to derive the value of            the variable ScalingMatrixDC[id−14] when id is greater than            13 as follows:

ScalingMatrixDCRec[id−14]=(ScalingMatrixDCPred+scaling_list_dc_coef[id−14])&255  (109)

When not present, the value of scaling_list_dc_coef[id−14] is inferredto be equal to 0. The value of scaling_list_dc_coef[id−14] shall be inthe range of −128 to 127, inclusive. The value ofScalingMatrixDCRec[id−14] shall be greater than 0.scaling_list_delta_coef[id][i] specifies the difference between thecurrent matrix coefficient ScalingList[id][i] and the previous matrixcoefficient ScalingList[id][i−1], when scaling_list_copy_mode_flag[id]is equal to 0. The value of scaling_list_delta_coef[id][i] shall be inthe range of −128 to 127, inclusive. Whenscaling_list_copy_mode_flag[id] is equal to 1, all elements ofScalingList[id] are set equal to 0.The (matrixSize)×(matrixSize) array ScalingMatrixRec[id] is derived asfollows:

ScalingMatrixRec[id][x][y]=(ScalingMatrixPred[x][y]+ScalingList[id][k])&255 with k=0 . . . (matrixSize*matrixSize−1),  (110)

-   -   x=DiagScanOrder[Log 2(matrixSize)][Log 2(matrixSize)][k][0], and    -   y=DiagScanOrder[Log 2(matrixSize)][Log 2(matrixSize)][k][1]        The value of ScalingMatrixRec[id][x][y] shall be greater than 0.

3.3. PH Syntax and Semantics

In the latest VVC draft text, the PH syntax and semantics are asfollows:

Descriptor picture_header_rbsp( ) {  picture_header_structure( ) rbsp_trailing_bits( ) }

The PH RBSP contains a PH syntax structure, i.e.,picture_header_structure( ).

Descriptor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1)  if(gdr_or_irap_pic_flag )   gdr_pic_flag u(1)  ph_inter_slice_allowed_flagu(1)  if( ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flagu(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v) ph_pic_order_cnt_Isb u(v)  if( gdr_or_irap_pic_flag )  no_output_of_prior_pics_flag u(1)  if( gdr_pic_flag )  recovery_poc_cnt ue(v)  for( i = 0; i < NumExtraPhBits; i++ )  ph_extra_bit[ i ] u(1)  if( sps_poc_msb_flag ) {  ph_poc_msb_present_flag u(1)   if( ph_poc_msb_present_flag )   poc_msb_val u(v)  }  if( sps_alf_enabled_flag && alf_info_in_ph_flag) {   ph_alf_enabled_flag u(1)   if( ph_alf_enabled_flag ) {   ph_num_alf_aps_ids_luma u(3)    for( i = 0; i <ph_num_alf_aps_ids_luma; i++ )     ph_alf_aps_id_luma[ i ] u(3)    if(ChromaArrayType != 0 )     ph_alf_chroma_idc u(2)    if(ph_alf_chroma_idc > 0)     ph_alf_aps_id_chroma u(3)    if(sps_ccalf_enabled_flag ) {     ph_cc_alf_cb_enabled_flag u(1)     if(ph_cc_alf_cb_enabled_flag )      ph_cc_alf_cb_aps_id u(3)    ph_cc_alf_cr_enabled_flag u(1)     if( ph_cc_alf_cr_enabled_flag )     ph_cc_alf_cr_aps_id u(3)    }   }  }  if( sps_lmcs_enabled_flag ) {  ph_lmcs_enabled_flag u(1)   if( ph_lmcs_enabled_flag ) {   ph_lmcs_aps_id u(2)    if( ChromaArrayType != 0 )    ph_chroma_residual_scale_flag u(1)   }  }  if(sps_scaling_list_enabled_flag ) {   ph_scaling_list_present_flag u(1)  if( ph_scaling_list_present_flag )    ph_scaling_list_aps_id u(3)  } if( sps_virtual_boundaries_enabled_flag &&!sps_virtual_boundaries_present_flag ) {  ph_virtual_boundaries_present_flag u(1)   if(ph_virtual_boundaries_present_flag ) {    ph_num_ver_virtual_boundariesu(2)    for( i = 0; i < ph_num_ver_virtual_boundaries; i++ )    ph_virtual_boundaries_pos_x[ i ] u(13)   ph_num_hor_virtual_boundaries u(2)    for( i = 0; i <ph_num_hor_virtual_boundaries; i++ )     ph_virtual_boundaries_pos_y[ i] u(13)   }  }  if( output_flag_present_flag )   pic_output_flag u(1) if( rpl_info_in_ph_flag )   ref_pic_lists()  if(partition_constraints_override_enabled_flag )  partition_constraints_override_flag u(1)  if(ph_intra_slice_allowed_flag ) {   if(partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)   ph_max_mtt_hierarchy_depth_intra_slice_luma ue(v)    if(ph_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {    ph_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)    ph_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)    }    if(qtbtt_dual_tree_intra_flag ) {    ph_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)    ph_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)     if(ph_max_mtt_hierarchy_depth_intra_slice_chroma != 0 ) { ph_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v) ph_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)     }    }   }  if( cu_qp_delta_enabled_flag )    ph_cu_qp_delta_subdiv_intra_sliceue(v)   if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_intra_slice ue(v)  }  if(ph_inter_slice_allowed_flag ) {   if(partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_inter_slice ue(v)   ph_max_mtt_hierarchy_depth_inter_slice ue(v)    if(ph_max_mtt_hierarchy_depth_inter_slice != 0 ) {    ph_log2_diff_max_bt_min_qt_inter_slice ue(v)    ph_log2_diff_max_tt_min_qt_inter_slice ue(v)    }   }   if(cu_qp_delta_enabled_flag )    ph_cu_qp_delta_subdiv_inter_slice ue(v)  if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_inter_slice ue(v)   if(sps_temporal_mvp_enabled_flag ) {    ph_temporal_mvp_enabled_flag u(1)   if( ph_temporal_mvp_enabled_flag && rpl_info_in_ph_flag ) {    ph_collocated_from_l0_flag u(1)     if( ( ph_collocated_from_l0_flag&&       num_ref_entries [ 0 ][ RplsIdx[ 0 ] ] > 1 ) | |       (!ph_collocated_from_l0_flag &&       num_ref_entries[ 1 ][ RplsIdx[ 1 ]] > 1 ) )      ph_collocated_ref_idx ue(v)    }   }   mvd_l1_zero_flagu(1)   if( sps_fpel_mmvd_enabled_flag )    ph_fpel_mmvd_enabled_flagu(1)   if( sps_bdof_pic_present_flag )    ph_disable_bdof_flag u(1)  if( sps_dmvr_pic_present_flag )    ph_disable_dmvr_flag u(1)   if(sps_prof_pic_present_flag )    ph_disable_prof_flag u(1)   if( (pps_weighted_pred_flag | | pps_weighted_bipred_flag ) &&wp_info_in_ph_flag )    pred_weight_table( )  }  if(qp_delta_info_in_ph_flag )   ph_qp_delta se(v)  if(sps_joint_cbcr_enabled_flag )   ph_joint_cbcr_sign_flag u(1)  if(sps_sao_enabled_flag && sao_info_in_ph_flag ) {  ph_sao_luma_enabled_flag u(1)   if( ChromaArrayType != 0 )   ph_sao_chroma_enabled_flag u(1)  }  if( sps_dep_quant_enabled_flag )  ph_dep_quant_enabled_flag u(1)  if( sps_sign_data_hiding_enabled_flag&& !ph_dep_quant_enabled_flag )   pic_sign_data_hiding_enabled_flag u(1) if( deblocking_filter_override_enabled_flag && dbf_info_in_ph_flag ) {  ph_deblocking_filter_override_flag u(1)   if(ph_deblocking_filter_override_flag ) {   ph_deblocking_filter_disabled_flag u(1)    if(!ph_deblocking_filter_disabled_flag ) {     ph_beta_offset_div2 se(v)    ph_tc_offset_div2 se(v)     ph_cb_beta_offset_div2 se(v)    ph_cb_tc_offset_div2 se(v)     ph_cr_beta_offset_div2 se(v)    ph_cr_tc_offset_div2 se(v)    }   }  }  if(picture_header_extension_present_flag ) {   ph_extension_length ue(v)  for( i = 0; i < ph_extension_length; i++ )    ph_extension_data_byte[i ] u(8)  } }The PH syntax structure contains information that is common for allslices of the coded picture associated with the PH syntax structure.gdr_or_irap_pic_flag equal to 1 specifies that the current picture is aGDR or IRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that thecurrent picture may or may not be a GDR or IRAP picture.gdr_pic_flag equal to 1 specifies the picture associated with the PH isa GDR picture. gdr_pic_flag equal to 0 specifies that the pictureassociated with the PH is not a GDR picture. When not present, the valueof gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag isequal to 0, the value of gdr_pic_flag shall be equal to 0.ph_inter_slice_allowed_flag equal to 0 specifies that all coded slicesof the picture have slice_type equal to 2. ph_inter_slice_allowed_flagequal to 1 specifies that there may or may not be one or more codedslices in the picture that have slice_type equal to 0 or 1.ph_intra_slice_allowed_flag equal to 0 specifies that all coded slicesof the picture have slice_type equal to 0 or 1.ph_intra_slice_allowed_flag equal to 1 specifies that there may or maynot be one or more coded slices in the picture that have slice_typeequal to 2. When not present, the value of ph_intra_slice_allowed_flagis inferred to be equal to 1.

-   -   NOTE 1—For bitstreams that are supposed to work subpicture based        bitstream merging without the need of changing PH NAL units, the        encoder is expected to set the values of both        ph_inter_slice_allowed_flag and ph_intra_slice_allowed_flag        equal to 1.        non_reference_picture_flag equal to 1 specifies the picture        associated with the PH is never used as a reference picture.        non_reference_picture_flag equal to 0 specifies the picture        associated with the PH may or may not be used as a reference        picture.        ph_pic_parameter_set_id specifies the value of        pps_pic_parameter_set_id for the PPS in use. The value of        ph_pic_parameter_set_id shall be in the range of 0 to 63,        inclusive.        It is a requirement of bitstream conformance that the value of        TemporalId of the PH shall be greater than or equal to the value        of TemporalId of the PPS that has pps_pic_parameter_set_id equal        to ph_pic_parameter_set_id.        ph_pic_order_cnt_lsb specifies the picture order count modulo        MaxPicOrderCntLsb for the current picture. The length of the        ph_pic_order_cnt_lsb syntax element is log        2_max_pic_order_cnt_lsb_minus4+4 bits. The value of the        ph_pic_order_cnt_lsb shall be in the range of 0 to        MaxPicOrderCntLsb−1, inclusive.        no_output_of_prior_pics_flag affects the output of        previously-decoded pictures in the DPB after the decoding of a        CLVSS picture that is not the first picture in the bitstream as        specified in Annex C.        recovery_poc_cnt specifies the recovery point of decoded        pictures in output order. If the current picture is a GDR        picture that is associated with the PH, and there is a picture        picA that follows the current GDR picture in decoding order in        the CLVS that has PicOrderCntVal equal to the PicOrderCntVal of        the current GDR picture plus the value of recovery_poc_cnt, the        picture picA is referred to as the recovery point picture.        Otherwise, the first picture in output order that has        PicOrderCntVal greater than the PicOrderCntVal of the current        picture plus the value of recovery_poc_cnt is referred to as the        recovery point picture. The recovery point picture shall not        precede the current GDR picture in decoding order. The value of        recovery_poc_cnt shall be in the range of 0 to        MaxPicOrderCntLsb−1, inclusive.        When the current picture is a GDR picture, the variable        RpPicOrderCntVal is derived as follows:

RpPicOrderCntVal=PicOrderCntVal+recovery_poc_cnt  (82)

-   -   NOTE 2—When gdr_enabled_flag is equal to 1 and PicOrderCntVal of        the current picture is greater than or equal to RpPicOrderCntVal        of the associated GDR picture, the current and subsequent        decoded pictures in output order are exact match to the        corresponding pictures produced by starting the decoding process        from the previous IRAP picture, when present, preceding the        associated GDR picture in decoding order.        ph_extra_bit[i] may be equal to 1 or 0. Decoders conforming to        this version of this Specification shall ignore the value of        ph_extra_bit[i]. Its value does not affect decoder conformance        to profiles specified in this version of specification.        ph_poc_msb_present_flag equal to 1 specifies that the syntax        element poc_msb_val is present in the PH.        ph_poc_msb_present_flag equal to 0 specifies that the syntax        element poc_msb_val is not present in the PH. When        vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is        equal to 0 and there is a picture in the current AU in a        reference layer of the current layer, the value of        ph_poc_msb_present_flag shall be equal to 0.        poc_msb_val specifies the POC MSB value of the current picture.        The length of the syntax element poc_msb_val is        poc_msb_len_minus1+1 bits.        ph_alf_enabled_flag equal to 1 specifies that adaptive loop        filter is enabled for all slices associated with the PH and may        be applied to Y, Cb, or Cr colour component in the slices.        ph_alf_enabled_flag equal to 0 specifies that adaptive loop        filter may be disabled for one, or more, or all slices        associated with the PH. When not present, ph_alf_enabled_flag is        inferred to be equal to 0.        ph_num_alf_aps_ids_luma specifies the number of ALF APSs that        the slices associated with the PH refers to.        ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id        of the i-th ALF APS that the luma component of the slices        associated with the PH refers to.        The value of alf_luma_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall        be equal to 1.        The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set id equal to ph_alf        aps_id_luma[i] shall be less than or equal to the TemporalId of        the picture associated with the PH.        ph_alf_chroma_idc equal to 0 specifies that the adaptive loop        filter is not applied to Cb and Cr colour components.        ph_alf_chroma_idc equal to 1 indicates that the adaptive loop        filter is applied to the Cb colour component. ph_alf_chroma_idc        equal to 2 indicates that the adaptive loop filter is applied to        the Cr colour component. ph_alf_chroma_idc equal to 3 indicates        that the adaptive loop filter is applied to Cb and Cr colour        components. When ph_alf_chroma_idc is not present, it is        inferred to be equal to 0.        ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id        of the ALF APS that the chroma component of the slices        associated with the PH refers to.        The value of alf_chroma_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_alf_aps_id_chroma shall        be equal to 1.        The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        ph_alf_aps_id_chroma shall be less than or equal to the        TemporalId of the picture associated with the PH.        ph_cc_alf_cb_enabled_flag equal to 1 specifies that        cross-component filter for Cb colour component is enabled for        all slices associated with the PH and may be applied to Cb        colour component in the slices. ph_cc_alf_cb_enabled_flag equal        to 0 specifies that cross-component filter for Cb colour        component may be disabled for one, or more, or all slices        associated with the PH. When not present,        ph_cc_alf_cb_enabled_flag is inferred to be equal to 0.        ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of        the ALF APS that the Cb colour component of the slices        associated with the PH refers to.        The value of alf_cc_cb_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id shall        be equal to 1.        The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        ph_cc_alf_cb_aps_id shall be less than or equal to the        TemporalId of the picture associated with the PH.        ph_cc_alf_cr_enabled_flag equal to 1 specifies that        cross-compoent filter for Cr colour component is enabled for all        slices associated with the PH and may be applied to Cr colour        component in the slices. ph_cc_alf_cr_enabled_flag equal to 0        specifies that cross-component filter for Cr colour component        may be disabled for one, or more, or all slices associated with        the PH. When not present, ph_cc_alf_cr_enabled_flag is inferred        to be equal to 0.        ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of        the ALF APS that the Cr colour component of the slices        associated with the PH refers to.        The value of alf_cc_cr_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id shall        be equal to 1.        The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        ph_cc_alf_cr_aps_id shall be less than or equal to the        TemporalId of the picture associated with the PH.        ph_lmes_enabled_flag equal to 1 specifies that luma mapping with        chroma scaling is enabled for all slices associated with the PH.        ph_lmcs_enabled_flag equal to 0 specifies that luma mapping with        chroma scaling may be disabled for one, or more, or all slices        associated with the PH. When not present, the value of        ph_lmcs_enabled_flag is inferred to be equal to 0.        ph_lmcs_aps_id specifies the adaptation_parameter set_id of the        LMCS APS that the slices associated with the PH refers to. The        TemporalId of the APS NAL unit having aps_params_type equal to        LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id        shall be less than or equal to the TemporalId of the picture        associated with PH.        ph_chroma_residual_scale_flag equal to 1 specifies that chroma        residual scaling is enabled for the all slices associated with        the PH. ph_chroma_residual_scale_flag equal to 0 specifies that        chroma residual scaling may be disabled for one, or more, or all        slices associated with the PH. When        ph_chroma_residual_scale_flag is not present, it is inferred to        be equal to 0.        ph_scaling_list_present_flag equal to 1 specifies that the        scaling list data used for the slices associated with the PH is        derived based on the scaling list data contained in the        referenced scaling list APS. ph_scaling_list_present_flag equal        to 0 specifies that the scaling list data used for the slices        associated with the PH is set to be equal to 16. When not        present, the value of ph_scaling_list_present_flag is inferred        to be equal to 0.        ph_scaling_list_aps_id specifies the adaptation_parameter_set_id        of the scaling list APS. The TemporalId of the APS NAL unit        having aps_params_type equal to SCALING_APS and        adaptation_parameter_set_id equal to ph_scaling_list_aps_id        shall be less than or equal to the TemporalId of the picture        associated with PH.        ph_virtual_boundaries_present_flag equal to 1 specifies that        information of virtual boundaries is signalled in the PH.        ph_virtual_boundaries_present_flag equal to 0 specifies that        information of virtual boundaries is not signalled in the PH.        When there is one or more than one virtual boundaries signalled        in the PH, the in-loop filtering operations are disabled across        the virtual boundaries in the picture. The in-loop filtering        operations include the deblocking filter, sample adaptive offset        filter, and adaptive loop filter operations. When not present,        the value of ph_virtual_boundaries_present_flag is inferred to        be equal to 0.        It is a requirement of bitstream conformance that, when        subpic_info_present_flag is equal to 1, the value of        ph_virtual_boundaries_present_flag shall be equal to 0.        The variable VirtualBoundariesPresentFlag is derived as follows:

VirtualBoundariesPresentFlag=0

if(sps_virtual_boundaries_enabled_flag)

VirtualBoundariesPresentFlag=sps_virtual_boundaries_present_flag∥

ph_virtual_boundaries_present_flag  (83)

ph_num_ver_virtual_boundaries specifies the number ofph_virtual_boundaries_pos_x[i] syntax elements that are present in thePH. When ph_num_ver_virtual_boundaries is not present, it is inferred tobe equal to 0.The variable NumVerVirtualBoundaries is derived as follows:

NumVerVirtualBoundaries=0

if(sps_virtual_boundaries_enabled_flag)

NumVerVirtualBoundaries=sps_virtual_boundaries_present_flag?

sps_num_ver_virtual_boundaries: ph_num_ver_virtual_boundaries  (84)

ph_virtual_boundaries_pos_x[i] specifies the location of the i-thvertical virtual boundary in units of luma samples divided by 8. Thevalue of ph_virtual_boundaries_pos_x[i] shall be in the range of 1 toCeil(pic_width_in_luma_samples÷8)−1, inclusive.The list VirtualBoundariesPosX[i] for i ranging from 0 toNumVerVirtualBoundaries−1, inclusive, in units of luma samples,specifying the locations of the vertical virtual boundaries, is derivedas follows:

for(i=0;i<NumVerVirtualBoundaries;i++)

VirtualBoundariesPosX[i]=(sps_virtual_boundaries_present_flag?

sps_virtual_boundaries_pos_x[i]: ph_virtual_boundaries_pos_x[i])*8  (85)

The distance between any two vertical virtual boundaries shall begreater than or equal to CtbSizeY luma samples.ph_num_hor_virtual_boundaries specifies the number ofph_virtual_boundaries_pos_y[i] syntax elements that are present in thePH. When ph_num_hor_virtual_boundaries is not present, it is inferred tobe equal to 0.The parameter NumHorVirtualBoundaries is derived as follows:

NumHorVirtualBoundaries=0

if(sps_virtual_boundaries_enabled_flag)

NumHorVirtualBoundaries=sps_virtual_boundaries_present_flag?

sps_num_hor_virtual_boundaries: ph_num_hor_virtual_boundaries  (86)

When sps_virtual_boundaries_enabled_flag is equal to 1 andph_virtual_boundaries_present_flag is equal to 1, the sum ofph_num_ver_virtual_boundaries and ph_num_hor_virtual_boundaries shall begreater than 0.ph_virtual_boundaries_pos_y[i] specifies the location of the i-thhorizontal virtual boundary in units of luma samples divided by 8. Thevalue of ph_virtual_boundaries_pos_y[i] shall be in the range of 1 toCeil(pic_height_in_luma_samples÷8)−1, inclusive.The list VirtualBoundariesPosY[i] for i ranging from 0 toNumHorVirtualBoundaries−1, inclusive, in units of luma samples,specifying the locations of the horizontal virtual boundaries, isderived as follows:

for(i=0;i<NumHorVirtualBoundaries;i++)

VirtualBoundariesPosY[i]=(sps_virtual_boundaries_present_flag?

sps_virtual_boundaries_pos_y[i]: ph_virtual_boundaries_pos_y[i])*8  (87)

The distance between any two horizontal virtual boundaries shall begreater than or equal to CtbSizeY luma samples.pic_output_flag affects the decoded picture output and removal processesas specified in Annex C. When pic_output_flag is not present, it isinferred to be equal to 1.partition_constraints_override_flag equal to 1 specifies that partitionconstraint parameters are present in the PH.partition_constraints_override_flag equal to 0 specifies that partitionconstraint parameters are not present in the PH. When not present, thevalue of partition_onstraints_override_flag is inferred to be equal to0.ph_log 2_diff_min_qt_min_cb_intra_slice_luma specifies the differencebetween the base 2 logarithm of the minimum size in luma samples of aluma leaf block resulting from quadtree splitting of a CTU and the base2 logarithm of the minimum coding block size in luma samples for lumaCUs in the slices with slice_type equal to 2 (I) associated with the PH.The value of ph_log 2_diff_min_qt_min_cb_intra_slice_luma shall be inthe range of 0 to Ctb Log 2SizeY−MinCb Log 2SizeY, inclusive. When notpresent, the value of ph_log 2diff_min_qt_min_cb_luma is inferred to beequal to sps_log 2_diff_min_qt_min_cb_intra_slice_luma.ph_max_mtt_hierarchy_depth_intra_slice_luma specifies the maximumhierarchy depth for coding units resulting from multi-type treesplitting of a quadtree leaf in slices with slice_type equal to 2 (I)associated with the PH. The value ofph_max_mtt_hierarchy_depth_intra_slice_luma shall be in the range of 0to 2*(Ctb Log 2SizeY−MinCb Log 2SizeY), inclusive. When not present, thevalue of ph_max_mtt_hierarchy_depth_intra_slice_luma is inferred to beequal to sps_max_mtt_hierarchy_depth_intra_slice_luma.ph_log 2_diff_max_bt_min_qt_intra_slice_luma specifies the differencebetween the base 2 logarithm of the maximum size (width or height) inluma samples of a luma coding block that can be split using a binarysplit and the minimum size (width or height) in luma samples of a lumaleaf block resulting from quadtree splitting of a CTU in slices withslice_type equal to 2 (I) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog 2SizeY−MinQt Log 2SizeIntraY, inclusive. When not present, the valueof ph_log 2_diff_max_bt_min_qt_intra_slice_luma is inferred to be equalto sps_log 2_diff_max_bt_min_qt_intra_slice_luma.ph_log 2_diff_max_tt_min_qt_intra_slice_luma specifies the differencebetween the base 2 logarithm of the maximum size (width or height) inluma samples of a luma coding block that can be split using a ternarysplit and the minimum size (width or height) in luma samples of a lumaleaf block resulting from quadtree splitting of a CTU in slices withslice_type equal to 2 (I) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog 2SizeY−MinQt Log 2SizeIntraY, inclusive. When not present, the valueof ph_log 2_diff_max_tt_min_qt_intra_slice_luma is inferred to be equalto sps_log 2_diff_max_tt_min_qt_intra_slice_luma.ph_log 2_diff_min_qt_min_cb_intra_slice_chroma specifies the differencebetween the base 2 logarithm of the minimum size in luma samples of achroma leaf block resulting from quadtree splitting of a chroma CTU withtreeType equal to DUAL_TREE_CHROMA and the base 2 logarithm of theminimum coding block size in luma samples for chroma CUs with treeTypeequal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I)associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of 0 toCtb Log 2SizeY−MinCb Log 2SizeY, inclusive. When not present, the valueof ph_log 2_diff_min_qt_min_cb_intra_slice_chroma is inferred to beequal to sps_log 2_diff_min_qt_min_cb_intra_slice_chroma.ph_max_mtt_hierarchy_depth_intra_slice_chroma specifies the maximumhierarchy depth for chroma coding units resulting from multi-type treesplitting of a chroma quadtree leaf with treeType equal toDUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) associatedwith the PH. The value of ph_max_mtt_hierarchy_depth_intra_slice_chromashall be in the range of 0 to 2*(Ctb Log 2SizeY−MinCb Log 2SizeY),inclusive. When not present, the value ofph_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be equal tosps_max_mtt_hierarchy_depth_intra_slice_chroma.ph_log 2_diff_max_bt_min_qt_intra_slice_chroma specifies the differencebetween the base 2 logarithm of the maximum size (width or height) inluma samples of a chroma coding block that can be split using a binarysplit and the minimum size (width or height) in luma samples of a chromaleaf block resulting from quadtree splitting of a chroma CTU withtreeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_intra_slice_chroma shall be in the range of 0 toCtb Log 2SizeY−MinQt Log 2SizeIntraC, inclusive. When not present, thevalue of ph_log 2_diff_max_bt_min_qt_intra_slice_chroma is inferred tobe equal to sps_log 2_diff_max_bt_min_qt_intra_slice_chroma.ph_log 2_diff_max_tt_min_qt_intra_slice_chroma specifies the differencebetween the base 2 logarithm of the maximum size (width or height) inluma samples of a chroma coding block that can be split using a ternarysplit and the minimum size (width or height) in luma samples of a chromaleaf block resulting from quadtree splitting of a chroma CTU withtreeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_intra_slice_chroma shall be in the range of 0 toCtb Log 2SizeY−MinQt Log 2SizeIntraC, inclusive. When not present, thevalue of ph_log 2_diff_max_tt_min_qt_intra_slice_chroma is inferred tobe equal to sps_log 2_diff_max_tt_min_qt_intra_slice_chromaph_cu_qp_delta_subdiv_intra_slice specifies the maximum cbSubdiv valueof coding units in intra slice that convey cu_qp_delta_abs andcu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_intra_sliceshall be in the range of 0 to 2*(Ctb Log 2SizeY−MinQt Log2SizelntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive.When not present, the value of ph_cu_qp_delta_subdiv_intra_slice isinferred to be equal to 0.ph_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum cbSubdivvalue of coding units in intra slice that conveycu_chroma_qp_offset_flag. The value ofph_cu_chroma_qp_offset_subdiv_intra_slice shall be in the range of 0 to2*(Ctb Log 2SizeY−MinQt Log2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive.When not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_sliceis inferred to be equal to 0.ph_log 2_diff_min_qt_min_cb_inter_slice specifies the difference betweenthe base 2 logarithm of the minimum size in luma samples of a luma leafblock resulting from quadtree splitting of a CTU and the base 2logarithm of the minimum luma coding block size in luma samples for lumaCUs in the slices with slice_type equal to 0 (B) or 1 (P) associatedwith the PH. The value of ph_log 2_diff_min_qt_min_cb_inter_slice shallbe in the range of 0 to Ctb Log 2SizeY−MinCb Log 2SizeY, inclusive. Whennot present, the value of ph_log 2diff_min_qt_min_cb_luma is inferred tobe equal to sps_log 2_diff_min_qt_min_cb_inter_slice.ph_max_mtt_hierarchy_depth_inter_slice specifies the maximum hierarchydepth for coding units resulting from multi-type tree splitting of aquadtree leaf in slices with slice_type equal to 0 (B) or 1 (P)associated with the PH. The value ofph_max_mtt_hierarchy_depth_inter_slice shall be in the range of 0 to2*(Ctb Log 2SizeY−MinCb Log 2SizeY), inclusive. When not present, thevalue of ph_max_mtt_hierarchy_depth_inter_slice is inferred to be equalto sps_max_mtt_hierarchy_depth_inter_slice.ph_log 2_diff_max_bt_min_qt_inter_slice specifies the difference betweenthe base 2 logarithm of the maximum size (width or height) in lumasamples of a luma coding block that can be split using a binary splitand the minimum size (width or height) in luma samples of a luma leafblock resulting from quadtree splitting of a CTU in the slices withslice_type equal to 0 (B) or 1 (P) associated with the PH. The value ofph_log 2_diff_max_bt_min_qt_inter_slice shall be in the range of 0 toCtb Log 2SizeY−MinQt Log 2SizeInterY, inclusive. When not present, thevalue of ph_log 2_diff_max_bt_min_qt_inter_slice is inferred to be equalto sps_log 2_diff_max_bt_min_qt_inter_slice.ph_log 2_diff_max_tt_min_qt_inter_slice specifies the difference betweenthe base 2 logarithm of the maximum size (width or height) in lumasamples of a luma coding block that can be split using a ternary splitand the minimum size (width or height) in luma samples of a luma leafblock resulting from quadtree splitting of a CTU in slices withslice_type equal to 0 (B) or 1 (P) associated with the PH. The value ofph_log 2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 toCtb Log 2SizeY−MinQt Log 2SizeInterY, inclusive. When not present, thevalue of ph_log 2_diff_max_tt_min_qt_inter_slice is inferred to be equalto sps_log 2_diff_max_tt_min_qt_inter_slice.ph_cu_qp_delta_subdiv_inter_slice specifies the maximum cbSubdiv valueof coding units that in inter slice convey cu_qp_delta_abs andcu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_inter_sliceshall be in the range of 0 to 2*(Ctb Log 2SizeY−MinQt Log2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice), inclusive. When notpresent, the value of ph_cu_qp_delta_subdiv_inter_slice is inferred tobe equal to 0.ph_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum cbSubdivvalue of coding units in inter slice that conveycu_chroma_qp_offset_flag. The value ofph_cu_chroma_qp_offset_subdiv_inter_slice shall be in the range of 0 to2*(Ctb Log 2SizeY−MinQt Log2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice), inclusive. When notpresent, the value of ph_cu_chroma_qp_offset_subdiv_inter_slice isinferred to be equal to 0.ph_temporal_mvp_enabled_flag specifies whether temporal motion vectorpredictors can be used for inter prediction for slices associated withthe PH. If ph_temporal_mvp_enabled_flag is equal to 0, the syntaxelements of the slices associated with the PH shall be constrained suchthat no temporal motion vector predictor is used in decoding of theslices. Otherwise (ph_temporal_mvp_enabled_flag is equal to 1), temporalmotion vector predictors may be used in decoding of the slicesassociated with the PH. When not present, the value ofph_temporal_mvp_enabled_flag is inferred to be equal to 0. When noreference picture in the DPB has the same spatial resolution as thecurrent picture, the value of ph_temporal_mvp_enabled_flag shall beequal to 0.The maximum number of subblock-based merging MVP candidates,MaxNumSubblockMergeCand, is derived as follows:

if( sps_affine_enabled_flag )  MaxNumSubblockMergeCand = 5 −five_minus_max_num_subblock_merge_cand (88) else MaxNumSubblockMergeCand = sps_sbtmvp_enabled_flag &&ph_temporal_mvp_enable_flagThe value of MaxNumSubblockMergeCand shall be in the range of 0 to 5,inclusive.ph_collocated_from_l0_flag equal to 1 specifies that the collocatedpicture used for temporal motion vector prediction is derived fromreference picture list 0. ph_collocated_from_l0_flag equal to 0specifies that the collocated picture used for temporal motion vectorprediction is derived from reference picture list 1.ph_collocated_ref_idx specifies the reference index of the collocatedpicture used for temporal motion vector prediction.When ph_collocated_from_l0_flag is equal to 1, ph_collocated_ref_idxrefers to an entry in reference picture list 0, and the value ofph_collocated_ref_idx shall be in the range of 0 tonum_ref_entries[0][RplsIdx[0] ]−1, inclusive. Whenph_collocated_from_l0_flag is equal to 0, ph_collocated_ref_idx refersto an entry in reference picture list 1, and the value ofph_collocated_ref_idx shall be in the range of 0 tonum_ref_entries[1][RplsIdx[1] ]−1, inclusive. When not present, thevalue of ph_collocated_ref_idx is inferred to be equal to 0.mvd_l1_zero_flag equal to 1 indicates that the mvd_coding(x0, y0, 1)syntax structure is not parsed and MvdL1[x0][y0][compIdx] andMvdCpL1[x0][y0][cpIdx][compIdx] are set equal to 0 for compIdx=0 . . . 1and cpIdx=0 . . . 2. mvd_11_zero_flag equal to 0 indicates that themvd_coding(x0, y0, 1) syntax structure is parsed.ph_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode withmotion vector difference uses integer sample precision in the slicesassociated with the PH. ph_fpel_mmvd_enabled_flag equal to 0 specifiesthat merge mode with motion vector difference can use fractional sampleprecision in the slices associated with the PH. When not present, thevalue of ph_fpel_mmvd_enabled_flag is inferred to be 0.ph_disable_bdof_flag equal to 1 specifies that bi-directional opticalflow inter prediction based inter bi-prediction is disabled in theslices associated with the PH. ph_disable_bdof_flag equal to 0 specifiesthat bi-directional optical flow inter prediction based interbi-prediction may or may not be enabled in the slices associated withthe PH.When ph_disable_bdof_flag is not present, the following applies:

-   -   If sps_bdof_enabled_flag is equal to 1, the value of        ph_disable_bdof_flag is inferred to be equal to 0.    -   Otherwise (sps_bdof_enabled_flag is equal to 0), the value of        ph_disable_bdof_flag is inferred to be equal to 1.        ph_disable_dmvr_flag equal to 1 specifies that decoder motion        vector refinement based inter bi-prediction is disabled in the        slices associated with the PH. ph_disable_dmvr_flag equal to 0        specifies that decoder motion vector refinement based inter        bi-prediction may or may not be enabled in the slices associated        with the PH.        When ph_disable_dmvr_flag is not present, the following applies:    -   If sps_dmvr_enabled_flag is equal to 1, the value of        ph_disable_dmvr_flag is inferred to be equal to 0.    -   Otherwise (sps_dmvr_enabled_flag is equal to 0), the value of        ph_disable_dmvr_flag is inferred to be equal to 1.        ph_disable_prof_flag equal to 1 specifies that prediction        refinement with optical flow is disabled in the slices        associated with the PH. ph_disable_prof_flag equal to 0        specifies that prediction refinement with optical flow may or        may not be enabled in the slices associated with the PH.        When ph_disable_prof_flag is not present, the following applies:    -   If sps_affine_prof_enabled_flag is equal to 1, the value of        ph_disable_prof_flag is inferred to be equal to 0.    -   Otherwise (sps_affine_prof_enabled_flag is equal to 0), the        value of ph_disable_prof_flag is inferred to be equal to 1.        ph_qp_delta specifies the initial value of Qp_(Y) to be used for        the coding blocks in the picture until modified by the value of        CuQpDeltaVal in the coding unit layer.        When qp_delta_info_in_ph_flag is equal to 1, the initial value        of the Qp_(Y) quantization parameter for all slices of the        picture, SliceQp_(Y), is derived as follows:

SliceQp_(Y)=26+init_qp_minus26+ph_qp_delta  (89)

The value of SliceQp_(Y) shall be in the range of −QpBdOffset to +63,inclusive.ph_joint_cbcr_sign_flag specifies whether, in transform units withtu_joint_cbcr_residual_flag[x0][y0] equal to 1, the collocated residualsamples of both chroma components have inverted signs. Whentu_joint_cbcr_residual_flag[x0][y0] equal to 1 for a transform unit,ph_joint_cbcr_sign_flag equal to 0 specifies that the sign of eachresidual sample of the Cr (or Cb) component is identical to the sign ofthe collocated Cb (or Cr) residual sample and ph_joint_cbcr_sign_flagequal to 1 specifies that the sign of each residual sample of the Cr (orCb) component is given by the inverted sign of the collocated Cb (or Cr)residual sample.ph_sao_luma_enabled_flag equal to 1 specifies that SAO is enabled forthe luma component in all slices associated with the PH;ph_sao_luma_enabled_flag equal to 0 specifies that SAO for the lumacomponent may be disabled for one, or more, or all slices associatedwith the PH. When ph_sao_luma_enabled_flag is not present, it isinferred to be equal to 0.ph_sao_chroma_enabled_flag equal to 1 specifies that SAO is enabled forthe chroma component in all slices associated with the PH;ph_sao_chroma_enabled_flag equal to 0 specifies that SAO for chromacomponent may be disabled for one, or more, or all slices associatedwith the PH. When ph_sao_chroma_enabled_flag is not present, it isinferred to be equal to 0.ph_dep_quant_enabled_flag equal to 0 specifies that dependentquantization is disabled for the current picture.ph_dep_quant_enabled_flag equal to 1 specifies that dependentquantization is enabled for the current picture. Whenph_dep_quant_enabled_flag is not present, it is inferred to be equal to0.pic_sign_data_hiding_enabled_flag equal to 0 specifies that sign bithiding is disabled for the current picture.pic_sign_data_hiding_enabled_flag equal to 1 specifies that sign bithiding is enabled for the current picture. Whenpic_sign_data_hiding_enabled_flag is not present, it is inferred to beequal to 0.ph_deblocking_filter_override_flag equal to 1 specifies that deblockingparameters are present in the PH. ph_deblocking_filter_override_flagequal to 0 specifies that deblocking parameters are not present in thePH. When not present, the value of ph_deblocking_filter_override_flag isinferred to be equal to 0.ph_deblocking_filter_disabled_flag equal to 1 specifies that theoperation of the deblocking filter is not applied for the slicesassociated with the PH. ph_deblocking_filter_disabled_flag equal to 0specifies that the operation of the deblocking filter is applied for theslices associated with the PH. When ph_deblocking_filter_disabled_flagis not present, it is inferred to be equal topps_deblocking_filter_disabled_flag.ph_beta_offset_div2 and ph_tc_offset_div2 specify the deblockingparameter offsets for β and tC (divided by 2) that are applied to theluma component for the slices associated with the PH. The values ofph_beta_offset_div2 and ph_tc_offset_div2 shall both be in the range of−12 to 12, inclusive. When not present, the values ofph_beta_offset_div2 and ph_te_offset_div2 are inferred to be equal topps_beta_offset_div2 and pps_te_offset_div2, respectively.ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 specify the deblockingparameter offsets for β and tC (divided by 2) that are applied to the Cbcomponent for the slices associated with the PH. The values ofph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 shall both be in therange of −12 to 12, inclusive. When not present, the values ofph_cb_beta_offset_div2 and ph_cb_te_offset_div2 are inferred to be equalto pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2, respectively.ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 specify the deblockingparameter offsets for β and tC (divided by 2) that are applied to the Crcomponent for the slices associated with the PH. The values ofph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 shall both be in therange of −12 to 12, inclusive. When not present, the values ofph_cr_beta_offset_div2 and ph_cr_te_offset_div2 are inferred to be equalto pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2, respectively.ph_extension_length specifies the length of the PH extension data inbytes, not including the bits used for signalling ph_extension_lengthitself. The value of ph_extension_length shall be in the range of 0 to256, inclusive. When not present, the value of ph_extension_length isinferred to be equal to 0.ph_extension_data_byte may have any value. Decoders conforming to thisversion of this Specification shall ignore the value ofph_extension_data_byte. Its value does not affect decoder conformance toprofiles specified in this version of specification.

3.4. SH Syntax and Semantics

In the latest VVC draft text, the SH syntax and semantics are asfollows:

Descriptor slice_header( ) {  picture_header_in_slice_header_flag u(1) if( picture_header_in_slice_header_flag )   picture_header_structure( ) if( subpic_info_present_flag )   slice_subpic_id u(v)  if( (rect_slice_flag && NumSlicesInSubpic[ CurrSubpicIdx ] > 1 ) | |    (!rect_slice_flag && NumTilesInPic > 1 ) )   slice_address u(v)  for( i =0; i < NumExtraShBits; i++ )   sh_extra_bit[ i ] u(1)  if(!rect_slice_flag && NumTilesInPic > 1 )   num_tiles_in_slice_minus1ue(v)  if( ph_inter_slice_allowed_flag )   slice_type ue(v)  if(sps_alf_enabled_flag && !alf_info_in_ph_flag ) {  slice_alf_enabled_flag u(1)   if( slice_alf_enabled_flag ) {   slice_num_alf_aps_ids_luma u(3)    for( i = 0; i <slice_num_alf_aps_ids_luma; i++ )     slice_alf_aps_id_luma[ i ] u(3)   if( ChromaArrayType != 0 )     slice_alf_chroma_idc u(2)    if(slice_alf_chroma_idc )     slice_alf_aps_id_chroma u(3)    if(sps_ccalf_enabled_flag ) {     slice_cc_alf_cb_enabled_flag u(1)     if(slice_cc_alf_cb_enabled_flag )      slice_cc_alf_cb_aps_id u(3)    slice_cc_alf_cr_enabled_flag u(1)     if(slice_cc_alf_cr_enabled_flag )      slice_cc_alf_cr_aps_id u(3)    }   } }  if( separate_colour_plane_flag = = 1 )   colour_plane_id u(2)  if(!rpl_info_in_ph_flag && ( ( nal_unit_type != IDR_W_RADL && nal_unit_type!=    IDR_N_LP) | | sps_idr_rpl_present_flag ) )   ref_pic_lists( )  if(( rpl_info_in_ph_flag | | ( ( nal_unit_type != IDR_W_RADL &&nal_unit_type !=    IDR_N_LP) | | sps_idr_rpl_present_flag ) ) &&    (slice_type != I && num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] > 1 ) | |    (slice_type == B && num_ref_entries[ 1 ][ RplsIdx[ 1 ] ] > 1)) {  num_ref_idx_active_override_flag u(1)   if(num_ref_idx_active_override_flag )    for( i = 0; i < ( slice_type = = B? 2: 1 ); i++ )     if( num_ref_entries[ i ][ RplsIdx[ i ] ] > 1 )     num_ref_idx_active_minus1 [ i ] ue(v)  }  if( slice_type != I ) {  if( cabac_init_present_flag )    cabac_init_flag u(1)   if(ph_temporal_mvp_enabled_flag && !rpl_info_in_ph_flag ) {    if(slice_type = = B )     slice_collocated_from_l0_flag u(1)    if( (slice_collocated_from_l0_flag && NumRefIdxActive[ 0 ] > 1 ) | |      ( !slice_collocated_from_l0_flag && NumRefIdxActive[ 1 ] > 1 ) )    slice_collocated_ref_idx ue(v)    }    if( !wp_info_in_ph_flag && (( pps_weighted_pred_flag && slice_type = = P ) | |     (pps_weighted_bipred_flag && slice_type == B ) ) )    pred_weight_table()  }  if( !qp_delta_info_in_ph_flag )   slice_qp_delta se(v)  if(pps_slice_chroma_qp_offsets_present_flag ) {   slice_cb_qp_offset se(v)  slice_cr_qp_offset se(v)   if( sps_joint_cbcr_enabled_flag )   slice_joint_cbcr_qp_offset se(v)  }  if(pps_cu_chroma_qp_offset_list_enabled_flag )  cu_chroma_qp_offset_enabled_flag u(1)  if( sps_sao_enabled_flag &&!sao_info_in_ph_flag ) {   slice_sao_luma_flag u(1)   if(ChromaArrayType != 0 )    slice_sao_chroma_flag u(1)  }  if(deblocking_filter_override_enabled_flag && !dbf_info_in_ph_flag )  slice_deblocking_filter_override_flag u(1)  if(slice_deblocking_filter_override_flag ) {  slice_deblocking_filter_disabled_flag u(1)   if(!slice_deblocking_filter_disabled_flag ) {    slice_beta_offset_div2se(v)    slice_tc_offset_div2 se(v)    slice_cb_beta_offset_div2 se(v)   slice_cb_tc_offset_div2 se(v)    slice_cr_beta_offset_div2 se(v)   slice_cr_tc_offset_div2 se(v)   }  } slice_ts_residual_coding_disabled_flag u(1)  if( ph_lmcs_enabled_flag )  slice_lmcs_enabled_flag u(1)  if( ph_scaling_list_enabled_flag )  slice_scaling_list_present_flag u(1)  if( NumEntryPoints > 0 ) {  offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )   entry_point_offset_minus1[ i ] u(v)  }  if(slice_header_extension_present_flag ) {   slice_header_extension_lengthue(v)   for( i = 0; i < slice_header_extension_length; i++)   slice_header_extension_data_byte[ i ] u(8)  }  byte_alignment( ) }The variable CuQpDeltaVal, specifying the difference between a lumaquantization parameter for the coding unit containing cu_qp_delta_absand its prediction, is set equal to 0. The variables CuQpOffset_(Cb),CuQpOffset_(Cr), and CuQpOffset_(CbCr), specifying values to be usedwhen determining the respective values of the Qp′_(Cb), Qp′_(Cr), andQp′_(CbCr) quantization parameters for the coding unit containingcu_chroma_qp_offset_flag, are all set equal to 0.picture_header_in_slice_header_flag equal to 1 specifies that the PHsyntax structure is present in the slice header.picture_header_in_slice_header_flag equal to 0 specifies that the PHsyntax structure is not present in the slice header. It is a requirementof bitstream conformance that the value ofpicture_header_in_slice-header_flag shall be the same in all codedslices in a CLVS.When picture_header_in_slice_header_flag is equal to 1 for a codedslice, it is a requirement of bitstream conformance that no VCL NAL unitwith nal_unit_type equal to PH_NUT shall be present in the CLVS.When picture_header_in_slice_header_flag is equal to 0, all coded slicesin the current picture shall have picture_header_in_slice_header_flag isequal to 0, and the current PU shall have a PH NAL unit.slice_subpic_id specifies the subpicture ID of the subpicture thatcontains the slice. If slice_subpic_id is present, the value of thevariable CurrSubpicIdx is derived to be such thatSubpicIdVal[CurrSubpicIdx] is equal to slice_subpic_id. Otherwise(slice_subpic_id is not present), CurrSubpicIdx is derived to be equalto 0. The length of slice_subpic_id is sps_subpic_id_len_minus1+1 bits.slice_address specifies the slice address of the slice. When notpresent, the value of slice_address is inferred to be equal to 0. Whenrect_slice_flag is equal to 1 and NumSlicesInSubpic[CurrSubpicIdx] isequal to 1, the value of slice_address is inferred to be equal to 0.If rect_slice_flag is equal to 0, the following applies:

-   -   The slice address is the raster scan tile index.    -   The length of slice_address is Ceil(Log 2 (NumTilesInPic)) bits.    -   The value of slice_address shall be in the range of 0 to        NumTilesInPic−1, inclusive.        Otherwise (rect_slice_flag is equal to 1), the following        applies:    -   The slice address is the subpicture-level slice index of the        slice.    -   The length of slice_address is Ceil(Log        2(NumSlicesInSubpic[CurrSubpicIdx])) bits.    -   The value of slice_address shall be in the range of 0 to        NumSlicesInSubpic[CurrSubpicIdx]−1, inclusive.        It is a requirement of bitstream conformance that the following        constraints apply:    -   If rect_slice_flag is equal to 0 or subpic_info_present_flag is        equal to 0, the value of slice_address shall not be equal to the        value of slice_address of any other coded slice NAL unit of the        same coded picture.    -   Otherwise, the pair of slice_subpic_id and slice_address values        shall not be equal to the pair of slice_subpic_id and        slice_address values of any other coded slice NAL unit of the        same coded picture.    -   The shapes of the slices of a picture shall be such that each        CTU, when decoded, shall have its entire left boundary and        entire top boundary consisting of a picture boundary or        consisting of boundaries of previously decoded CTU(s).        sh_extra_bit[i] may be equal to 1 or 0. Decoders conforming to        this version of this Specification shall ignore the value of        sh_extra_bit[i]. Its value does not affect decoder conformance        to profiles specified in this version of specification.        num_tiles_in_slice_minus1 plus 1, when present, specifies the        number of tiles in the slice. The value of        num_tiles_in_slice_minus1 shall be in the range of 0 to        NumTilesInPic−1, inclusive.        The variable NumCtusInCurrSlice, which specifies the number of        CTUs in the current slice, and the list CtbAddrInCurrSlice[i],        for i ranging from 0 to NumCtusInCurrSlice−1, inclusive,        specifying the picture raster scan address of the i-th CTB        within the slice, are derived as follows:

if( rect_slice_flag ) {  picLevelSliceIdx = slice_address  for( j = 0; j< CurrSubpicIdx; j++ )   picLevelSliceIdx += NumSlicesInSubpic[ j ] NumCtusInCurrSlice = NumCtusInSlice[ picLevelSliceIdx ]  for( i = 0; i< NumCtusInCurrSlice; i++ )   CtbAddrInCurrSlice[ i ] = CtbAddrInSlice[picLevelSliceIdx ][ i ] (117) } else {  NumCtusInCurrSlice = 0  for(tileIdx = slice_address; tileIdx <= slice_address +num_tiles_in_slice_minus1; tileIdx++ ) {   tileX = tileIdx %NumTileColumns   tileY = tileIdx / NumTileColumns   for( ctbY =tileRowBd[ tileY ]; ctbY < tileRowBd[ tileY + 1 ]; ctbY++ ) {    for(ctbX = tileColBd[ tileX ]; ctbX < tileColBd[ tileX + 1 ]; ctbX++ ) {    CtbAddrInCurrSlice[ NumCtusInCurrSlice ] = ctbY * Pic WidthInCtb +ctbX     NumCtusInCurrSlice++    }   }  } }The variables SubpicLeftBoundaryPos, SubpicTopBoundaryPos,SubpicRightBoundaryPos, and SubpicBotBoundaryPos are derived as follows:

if( subpic_treated_as_pic_flag[ CurrSubpicIdx ] ) { SubpicLeftBoundaryPos = subpic_ctu_top_left_x[ CurrSubpicIdx ] *CtbSize Y  SubpicRightBoundaryPos = Min( pic_width_max_in_luma_samples −1,   ( subpic_ctu_top_left_x[ CurrSubpicIdx ] +   subpic_width_minus1[CurrSubpicIdx ] + 1 ) * CtbSizeY − 1)  SubpicTopBoundaryPos =subpic_ctu_top_left_y[ CurrSubpicIdx ] *CtbSizeY (118) SubpicBotBoundaryPos = Min( pic_height_max_in_luma_samples − 1,   (subpic_ctu_top_left_y[ CurrSubpicIdx ] +   subpic_height_minus1[CurrSubpicIdx ] + 1 ) * CtbSizeY − 1 ) }slice_type specifies the coding type of the slice according to Table 9.

TABLE 9 Name association to slice_type slice_type Name of slice_type 0 B(B slice) 1 P (P slice) 2 I (I slice)When not present, the value of slice_type is inferred to be equal to 2.When ph_intra_slice_allowed_flag is equal to 0, the value of slice_typeshall be equal to 0 or 1. When nal_unit_type is in the range ofIDR_W_RADL to CRA_NUT, inclusive, andvps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1,slice_type shall be equal to 2. The variables MinQt Log 2SizeY, MinQtLog 2SizeC, MinQtSizeY, MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY,MaxTtSizeY, MaxTtSizeC, MinTtSizeY, MaxMttDepthY and MaxMttDepthC arederived as follows:

-   -   If slice_type equal to 2 (I), the following applies:

MinQt Log 2SizeY=MinCb Log 2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_luma  (119)

MinQt Log 2SizeC=MinCb Log 2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_chroma  (120)

MaxBtSizeY=1<<(MinQt Log 2SizeY+ph_log2_diff_max_bt_min_qt_intra_slice_luma)  (121)

MaxBtSizeC=1<<(MinQt Log 2SizeC+ph_log2_diff_max_bt_min_qt_intra_slice_chroma)  (122)

MaxTtSizeY=1<<(MinQt Log 2SizeY+ph_log2_diff_max_tt_min_qt_intra_slice_luma)  (123)

MaxTtSizeC=1<<(MinQt Log 2SizeC+ph_log2_diff_max_tt_min_qt_intra_slice_chroma)  (124)

MaxMttDepthY=ph_max_mtt_hierarchy_depth_intra_slice_luma  (125)

MaxMttDepthC=ph_max_mtt_hierarchy_depth_intra_slice_chroma  (126)

CuQpDeltaSubdiv=ph_cu_qp_delta_subdiv_intra_slice  (127)

CuChromaQpOffsetSubdiv=ph_cu_chroma_qp_offset_subdiv_intra_slice  (128)

-   -   Otherwise (slice_type equal to 0 (B) or 1 (P)), the following        applies:

MinQt Log 2SizeY=MinCb Log 2SizeY+ph_log2_diff_min_qt_min_cb_inter_slice  (129)

MinQt Log 2SizeC=MinCb Log 2SizeY+ph_log2_diff_min_qt_min_cb_inter_slice  (130)

MaxBtSizeY=1<<(MinQt Log 2SizeY+ph_log2_diff_max_bt_min_qt_inter_slice)  (131)

MaxBtSizeC=1<<(MinQt Log 2SizeC+ph_log2_diff_max_bt_min_qt_inter_slice)  (132)

MaxTtSizeY=1<<(MinQt Log 2SizeY+ph_log2_diff_max_tt_min_qt_inter_slice)  (133)

MaxTtSizeC=1<<(MinQt Log 2SizeC+ph_log2_diff_max_tt_min_qt_inter_slice)  (134)

MaxMttDepthY=ph_max_mtt_hierarchy_depth_inter_slice  (135)

MaxMttDepthC=ph_max_mtt_hierarchy_depth_inter_slice  (136)

CuQpDeltaSubdiv=ph_cu_qp_delta_subdiv_inter_slice  (137)

CuChromaQpOffsetSubdiv=ph_cu_chroma_qp_offset_subdiv_inter_slice  (138)

The following applies:

MinQtSizeY=1<<MinQt Log 2SizeY  (139)

MinQtSizeC=1<<MinQt Log 2SizeC  (140)

MinBtSizeY=1<<MinCb Log 2SizeY  (141)

MinTtSizeY=1<<MinCb Log 2SizeY  (142)

slice_alf_enabled_flag equal to 1 specifies that adaptive loop filter isenabled and may be applied to Y, Cb, or Cr colour component in a slice.slice_alf_enabled_flag equal to 0 specifies that adaptive loop filter isdisabled for all colour components in a slice. When not present, thevalue of slice_alf_enabled_flag is inferred to be equal toph_alf_enabled_flag.slice_num_alf_aps_ids_luma specifies the number of ALF APSs that theslice refers to. When slice_alf_enabled_flag is equal to 1 andslice_num_alf aps_ids_luma is not present, the value ofslice_num_alf_aps_ids_luma is inferred to be equal to the value ofph_num_alf aps_ids_luma.slice_alf aps_id_luma[i] specifies the adaptation_parameter_set_id ofthe i-th ALF APS that the luma component of the slice refers to. TheTemporalId of the APS NAL unit having aps_params_type equal to ALF_APSand adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i] shallbe less than or equal to the TemporalId of the coded slice NAL unit.When slice_alf_enabled flag is equal to 1 and slice_alf aps_id_luma[i]is not present, the value of slice_alf_aps_id_luma[i] is inferred to beequal to the value of ph alf aps_id_luma[i].The value of alf_luma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_alf_aps_id_luma[i] shall be equal to 1.slice_alf_chroma_idc equal to 0 specifies that the adaptive loop filteris not applied to Cb and Cr colour components. slice_alf_chroma_idcequal to 1 indicates that the adaptive loop filter is applied to the Cbcolour component. slice_alf_chroma_idc equal to 2 indicates that theadaptive loop filter is applied to the Cr colour component.slice_alf_chroma_idc equal to 3 indicates that the adaptive loop filteris applied to Cb and Cr colour components. When slice_alf_chroma_idc isnot present, it is inferred to be equal to ph_alf_chroma_idc.slice_alf_aps_id_chroma specifies the adaptation_parameter_set_id of theALF APS that the chroma component of the slice refers to. The TemporalIdof the APS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_alf_enabled flag is equal to 1 and slice_alf_aps_id_chroma is notpresent, the value of slice_alf aps_id_chroma is inferred to be equal tothe value of ph_alf aps_id_chroma.The value of alf_chroma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_alf_aps_id_chroma shall be equal to 1.slice_cc_alf_cb_enabled_flag equal to 0 specifies that thecross-component filter is not applied to the Cb colour component.slice_cc_alf_cb_enabled_flag equal to 1 indicates that thecross-component filter is enabled and may be applied to the Cb colourcomponent. When slice_cc_alf_cb_enabled_flag is not present, it isinferred to be equal to ph_cc_alf_cb_enabled_flag.slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id thatthe Cb colour component of the slice refers to. The TemporalId of theAPS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_cc_alf_cb_enabled flag is equal to 1 and slice_cc_alf_cb_aps_id isnot present, the value of slice_cc_alf_cb_aps_id is inferred to be equalto the value of ph_cc_alf cb_aps_id.The value of alf_cc_cb_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_cc_alf_cb_aps_id shall be equal to 1.slice_cc_alf_cr_enabled_flag equal to 0 specifies that thecross-component filter is not applied to the Cr colour component.slice_cc_alf_cb_enabled_flag equal to 1 indicates that thecross-component adaptive loop filter is enabled and may be applied tothe Cr colour component. When slice_cc_alf_cr_enabled_flag is notpresent, it is inferred to be equal to ph_cc_alf_cr_enabled_flag.slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id thatthe Cr colour component of the slice refers to. The TemporalId of theAPS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id isnot present, the value of slice_cc_alf_cr_aps_id is inferred to be equalto the value of ph_cc_alf_cr_aps_id.The value of alf_cc_cr_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_cc_alf_cr_aps_id shall be equal to 1.colour_plane_id identifies the colour plane associated with the currentslice when separate_colour_plane_flag is equal to 1. The value ofcolour_plane_id shall be in the range of 0 to 2, inclusive.colour_plane_id values 0, 1 and 2 correspond to the Y, Cb and Cr planes,respectively. The value 3 of colour_plane_id is reserved for future useby ITU-T|ISO/IEC.

-   -   NOTE 1—There is no dependency between the decoding processes of        different colour planes of one picture.        num_ref_idx_active_override_flag equal to 1 specifies that the        syntax element num_ref_idx_active_minus1 [0] is present for P        and B slices and the syntax element num_ref_idx_active_minus1[1]        is present for B slices. num_ref_idx_active_override_flag equal        to 0 specifies that the syntax elements        num_ref_idx_active_minus1 [0] and num_ref_idx_active_minus1[1]        are not present. When not present, the value of        num_ref_idx_active_override_flag is inferred to be equal to 1.        num_ref_idx_active_minus1[i] is used for the derivation of the        variable NumRefIdxActive[i] as specified by Equation 143. The        value of num_ref_idx_active_minus1[i] shall be in the range of 0        to 14, inclusive.        For i equal to 0 or 1, when the current slice is a B slice,        num_ref_idx_active_override_flag is equal to 1, and        num_ref_idx_active_minus1[i] is not present,        num_ref_idx_active_minus1[i] is inferred to be equal to 0.        When the current slice is a P slice,        num_ref_idx_active_override_flag is equal to 1, and        num_ref_idx_active_minus1[0] is not present,        num_ref_idx_active_minus1[0] is inferred to be equal to 0.        The variable NumRefIdxActive[i] is derived as follows:

for( i = 0; i < 2; i++ ) {  if( slice_type = = B | | ( slice_type = = P&& i = = 0 ) ) {   if( num_ref_idx_active_override_flag )   NumRefIdxActive[ i ] = num_ref_idx_active_minus1[ i ] + 1 (143)  else {    if( num_ref_entries[ i ][ RplsIdx[ i ] ] >=num_ref_idx_default_active_minus1[ i ] + 1 )     NumRefIdxActive[ i ] =num_ref_idx_default_active_minus1[ i ] + 1    else     NumRefIdxActive[i ] = num_ref_entries[ i ][ RplsIdx[ i ] ]   }  } else /* slice_type = =I | | ( slice_type = = P && i = = 1) */   NumRefIdxActive[ i ] = 0 }The value of NumRefIdxActive[i]−1 specifies the maximum reference indexfor reference picture list i that may be used to decode the slice. Whenthe value of NumRefIdxActive[i] is equal to 0, no reference index forreference picture list i may be used to decode the slice.When the current slice is a P slice, the value of NumRefIdxActive[0]shall be greater than 0.When the current slice is a B slice, both NumRefIdxActive[0] andNumRefIdxActive[1] shall be greater than 0.cabac_init_flag specifies the method for determining the initializationtable used in the initialization process for context variables. Whencabac_init_flag is not present, it is inferred to be equal to 0.slice_collocated_from_l0_flag equal to 1 specifies that the collocatedpicture used for temporal motion vector prediction is derived fromreference picture list 0. slice_collocated_from_l0_flag equal to 0specifies that the collocated picture used for temporal motion vectorprediction is derived from reference picture list 1.When slice_type is equal to B or P, ph_temporal_mvp_enabled_flag isequal to 1, and slice_collocated_from_l0_flag is not present, thefollowing applies:

-   -   If rpl_info_in_ph_flag is equal to 1,        slice_collocated_from_l0_flag is inferred to be equal to        ph_collocated_from_l0_flag.    -   Otherwise (rpl_info_in_ph_flag is equal to 0 and slice_type is        equal to P), the value of slice_collocated_from_l0_flag is        inferred to be equal to 1.        slice_collocated_ref_idx specifies the reference index of the        collocated picture used for temporal motion vector prediction.        When slice_type is equal to P or when slice_type is equal to B        and slice_collocated_from_l0_flag is equal to 1,        slice_collocated_ref_idx refers to an entry in reference picture        list 0, and the value of slice_collocated_ref_idx shall be in        the range of 0 to NumRefIdxActive[0]−1, inclusive.        When slice_type is equal to B and slice_collocated_from_l0_flag        is equal to 0, slice_collocated_ref_idx refers to an entry in        reference picture list 1, and the value of        slice_collocated_ref_idx shall be in the range of 0 to        NumRefIdxActive[1]−1, inclusive.        When slice_collocated_ref_idx is not present, the following        applies:    -   If rpl_info_in_ph_flag is equal to 1, the value of        slice_collocated_ref_idx is inferred to be equal to        ph_collocated_ref_idx.    -   Otherwise (rpl_info_in_ph_flag is equal to 0), the value of        slice_collocated_ref_idx is inferred to be equal to 0.        It is a requirement of bitstream conformance that the picture        referred to by slice_collocated_ref_idx shall be the same for        all slices of a coded picture.        It is a requirement of bitstream conformance that the values of        pic_width_in_luma_samples and pic_height_in_luma_samples of the        reference picture referred to by slice_collocated_ref_idx shall        be equal to the values of pic_width_in_luma_samples and        pic_height_in_luma_samples, respectively, of the current        picture, and RprConstraintsActive[slice_collocated_from_l0_flag?        0:1][slice_collocated_ref_idx] shall be equal to 0.        slice_qp_delta specifies the initial value of Qp_(Y) to be used        for the coding blocks in the slice until modified by the value        of CuQpDeltaVal in the coding unit layer.        When qp_delta_info_in_ph_flag is equal to 0, the initial value        of the Qp_(Y) quantization parameter for the slice, SliceQp_(Y),        is derived as follows:

SliceQp_(Y)=26+init_qp_minus26+slice_qp_delta  (144)

The value of SliceQp_(Y) shall be in the range of −QpBdOffset to +63,inclusive.When either of the following conditions is true:

-   -   The value of wp_info_in_ph_flag is equal to 1,        pps_weighted_pred_flag is equal to 1, and slice_type is equal to        P.    -   The value of wp_info_in_ph_flag is equal to 1,        pps_weighted_bipred_flag is equal to 1, and slice_type is equal        to B.        the following applies:    -   The value of NumRefIdxActive[0] shall be less than or equal to        the value of NumWeightsL0.    -   For each reference picture index RefPicList[0][i] for i in the        range of 0 to NumRefIdxActive[0]−1, inclusive, the luma weight,        Cb weight, and Cr weight that apply to the reference picture        index are LumaWeightL0[i], ChromaWeightL0[0][i], and        ChromaWeightL0[1][i], respectively.        When wp_info_in_ph_flag is equal to 1, pps_weighted_bipred_flag        is equal to 1, and slice_type is equal to B, the following        applies:    -   The value of NumRefIdxActive[1] shall be less than or equal to        the value of NumWeightsL1.    -   For each reference picture index RefPicList[1][i] for i in the        range of 0 to NumRefIdxActive[1]−1, inclusive, the luma weight,        Cb weight, and Cr weight that apply to the reference picture        index are LumaWeightL1[i],        ChromaWeightL1[0][i], and ChromaWeightL1[1][i], respectively.        slice_cb_qp_offset specifies a difference to be added to the        value of pps_cb_qp_offset when determining the value of the        Qp′_(Cb) quantization parameter. The value of slice_cb_qp_offset        shall be in the range of −12 to +12, inclusive. When        slice_cb_qp_offset is not present, it is inferred to be equal        to 0. The value of pps_cb_qp_offset+slice_cb_qp_offset shall be        in the range of −12 to +12, inclusive.        slice_cr_qp_offset specifies a difference to be added to the        value of pps_cr_qp_offset when determining the value of the        Qp′_(Cr) quantization parameter. The value of slice_cr_qp_offset        shall be in the range of −12 to +12, inclusive. When        slice_cr_qp_offset is not present, it is inferred to be equal        to 0. The value of pps_cr_qp_offset+slice_cr_qp_offset shall be        in the range of −12 to +12, inclusive.        slice_joint_cbcr_qp_offset specifies a difference to be added to        the value of pps_joint_cbcr_qp_offset_value when determining the        value of the Qp′_(CbCr). The value of slice_joint_cbcr_qp_offset        shall be in the range of −12 to +12, inclusive. When        slice_joint_cbcr_qp_offset is not present, it is inferred to be        equal to 0. The value of        pps_joint_cbcr_qp_offset_value+slicejoint_cbcr_qp_offset shall        be in the range of −12 to +12, inclusive.        cu_chroma_qp_offset_enabled_flag equal to 1 specifies that the        cu_chroma_qp_offset_flag may be present in the transform unit        and palette coding syntax. cu_chroma_qp_offset_enabled_flag        equal to 0 specifies that the cu_chroma_qp_offset_flag is not        present in the transform unit or palette coding syntax. When not        present, the value of cu_chroma_qp_offset_enabled_flag is        inferred to be equal to 0.        slice_sao_luma_flag equal to 1 specifies that SAO is enabled for        the luma component in the current slice; slice_sao_luma_flag        equal to 0 specifies that SAO is disabled for the luma component        in the current slice. When slice_sao_luma_flag is not present,        it is inferred to be equal to ph_sao_luma_enabled_flag.        slice_sao_chroma_flag equal to 1 specifies that SAO is enabled        for the chroma component in the current slice;        slice_sao_chroma_flag equal to 0 specifies that SAO is disabled        for the chroma component in the current slice. When        slice_sao_chroma_flag is not present, it is inferred to be equal        to ph_sao_chroma_enabled_flag.        slice_deblocking_filter_override_flag equal to 1 specifies that        deblocking parameters are present in the slice header.        slice_deblockingjfilter_override_flag equal to 0 specifies that        deblocking parameters are not present in the slice header. When        not present, the value of slice_deblockingjfilter_override_flag        is inferred to be equal to ph_deblocking_filter_override_flag.        slice_deblocking_filter_disabled_flag equal to 1 specifies that        the operation of the deblocking filter is not applied for the        current slice. slice_deblockingjfilter_disabled_flag equal to 0        specifies that the operation of the deblocking filter is applied        for the current slice. When        slice_deblocking_filter_disabled_flag is not present, it is        inferred to be equal to ph_deblocking_filter_disabled_flag.        slice_beta_offset_div2 and slice_tc_offset_div2 specify the        deblocking parameter offsets for β and tC (divided by 2) that        are applied to the luma component for the current slice. The        values of slice_beta_offset_div2 and slice_tc_offset_div2 shall        both be in the range of −12 to 12, inclusive. When not present,        the values of slice_beta_offset_div2 and slice_tc_offset_div2        are inferred to be equal to ph_beta_offset_div2 and        ph_te_offset_div2, respectively.        slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify        the deblocking parameter offsets for β and tC (divided by 2)        that are applied to the Cb component for the current slice. The        values of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2        shall both be in the range of −12 to 12, inclusive. When not        present, the values of slice_cb_beta_offset_div2 and        slice_cb_tc_offset_div2 are inferred to be equal to        ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2, respectively.        slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify        the deblocking parameter offsets for β and tC (divided by 2)        that are applied to the Cr component for the current slice. The        values of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2        shall both be in the range of −12 to 12, inclusive. When not        present, the values of slice_cr_beta_offset_div2 and        slice_cr_tc_offset_div2 are inferred to be equal to        ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2, respectively.        slice_ts_residual_coding_disabled_flag equal to 1 specifies that        the residual_coding( ) syntax structure is used to parse the        residual samples of a transform skip block for the current        slice. slice_ts_residual_coding_disabled_flag equal to 0        specifies that the residual_ts_coding( ) syntax structure is        used to parse the residual samples of a transform skip block for        the current slice. When slice_ts_residual_coding_disabled_flag        is not present, it is infered to be equal to 0.        slice_lmes_enabled_flag equal to 1 specifies that luma mapping        with chroma scaling is enabled for the current slice.        slice_lmcs_enabled_flag equal to 0 specifies that luma mapping        with chroma scaling is not enabled for the current slice. When        slice_lmcs_enabled_flag is not present, it is inferred to be        equal to 0.        slice_scaling_list_present_flag equal to 1 specifies that the        scaling list data used for the current slice is derived based on        the scaling list data contained in the referenced scaling list        APS with aps_params_type equal to SCALING_APS and        adaptation_parameter_set_id equal to ph_scaling_list_aps_id.        slice_scaling_list_present_flag equal to 0 specifies that the        scaling list data used for the current picture is the default        scaling list data derived specified in clause 7.4.3.21. When not        present, the value of slice_scaling_list_present_flag is        inferred to be equal to 0.        The variable NumEntryPoints, which specifies the number of entry        points in the current slice, is derived as follows:

NumEntryPoints = 0 for( i = 1; i < NumCtusInCurrSlice; i++ ) {  ctbAddrX= CtbAddrInCurrSlice[ i ] % Pic WidthInCtbs Y  ctbAddrY =CtbAddrInCurrSlice[ i ] / Pic WidthInCtbsY (145) CtbAddrInCurrSlice[ i −1 ] % Pic WidthInCtbs Y prevCtbAddrX =  prevCtbAddrY =CtbAddrInCurrSlice[ i − 1 ] / Pic Width InCtbsY  if( CtbToTileRowBd[ctbAddrY ] != CtbToTileRowBd[ prevCtbAddrY ] | |    CtbToTileColBd[ctbAddrX ] != CtbToTileColBd[ prevCtbAddrX ] | |    ( ctbAddrY !=prevCtbAddrY && sps_wpp_entry_point_offsets_present_flag ) )  NumEntryPoints++ }offset_len_minus1 plus 1 specifies the length, in bits, of theentry_point_offset_minus1[i] syntax elements. The value ofoffset_len_minus1 shall be in the range of 0 to 31, inclusive.entry_point_offset_minus1[i] plus 1 specifies the i-th entry pointoffset in bytes, and is represented by offset_len_minus1 plus 1 bits.The slice data that follow the slice header consists of NumEntryPoints+1subsets, with subset index values ranging from 0 to NumEntryPoints,inclusive. The first byte of the slice data is considered byte 0. Whenpresent, emulation prevention bytes that appear in the slice dataportion of the coded slice NAL unit are counted as part of the slicedata for purposes of subset identification. Subset 0 consists of bytes 0to entry_point_offset_minus1[0], inclusive, of the coded slice data,subset k, with k in the range of 1 to NumEntryPoints−1, inclusive,consists of bytes firstByte[k] to lastByte[k], inclusive, of the codedslice data with firstByte[k] and lastByte[k] defined as:

firstByte[k]=Σ _(n=1) ^(k)(entry_point_offset_minus1[n−1]+1)  (146)

lastByte[k]=firstByte[k]+entry_point_offset_minus1[k]  (147)

The last subset (with subset index equal to NumEntryPoints) consists ofthe remaining bytes of the coded slice data. Whensps_entropy_coding_sync_enabled_flag is equal to 0 and the slicecontains one or more complete tiles, each subset shall consist of allcoded bits of all CTUs in the slice that are within the same tile, andthe number of subsets (i.e., the value of NumEntryPoints+1) shall beequal to the number of tiles in the slice.When sps_entropy_coding_sync_enabled_flag is equal to 0 and the slicecontains a subset of CTU rows from a single tile, the NumEntryPointsshall be 0, and the number of subsets shall be 1. The subset shallconsist of all coded bits of all CTUs in the slice.When sps_entropy_coding_sync_enabled_flag is equal to 1, each subset kwith k in the range of 0 to NumEntryPoints, inclusive, shall consist ofall coded bits of all CTUs in a CTU row within a tile, and the number ofsubsets (i.e., the value of NumEntryPoints+1) shall be equal to thetotal number of tile-specific CTU rows in the slice.slice_header_extension_length specifies the length of the slice headerextension data in bytes, not including the bits used for signallingslice_header_extension_length itself. The value ofslice_header_extensionlength shall be in the range of 0 to 256,inclusive. When not present, the value of slice_header_extensionlengthis inferred to be equal to 0.slice_header_extension_data_byte[i] may have any value. Decodersconforming to this version of this Specification shall ignore the valuesof all the slice_header_extension_data_byte[i] syntax elements. Itsvalue does not affect decoder conformance to profiles specified in thisversion of specification.

3.5. Chroma QP Mapping Table

In clause 7.3.2.3 of JVET-Q2001-vC, the SPS includes a structure namedchroma QP table, shown as follows:

Descriptor seq_parameter_set_rbsp( ) {  ... ...  if( ChromaArrayType !=0 ) {   sps_joint_cbcr_enabled_flag u(1)   same_qp_table_for_chroma u(1)  numQpTables = same_qp_table_for_chroma ? 1 : (sps_joint_cbcr_enabled_flag ? 3 : 2 )   for( i = 0; i < numQpTables; i++) {    qp_table_start_minus26[ i ] se(v)   num_points_in_qp_table_minus1[ i ] ue(v)    for( j = 0; j <=num_points_in_qp_table_minus1[ i ]; j++ ) {     delta_qp_in_val_minus1[i ][ j ] ue(v)     delta_qp_diff_val[ i ][ j ] ue(v)    }   }  }  ......They are with the following semantics and QP table derivation:sps_joint_cbcr_enabled_flag equal to 0 specifies that the joint codingof chroma residuals is disabled. sps_joint_cbcr_enabled_flag equal to 1specifies that the joint coding of chroma residuals is enabled. When notpresent, the value of sps_joint_cbcr_enabled_flag is inferred to beequal to 0.same_qp_table_for_chroma equal to 1 specifies that only one chroma QPmapping table is signalled and this table applies to Cb and Cr residualsand additionally to joint Cb-Cr residuals whensps_joint_cbcr_enabled_flag is equal to 1. same_qp_table_for_chromaequal to 0 specifies that chroma QP mapping tables, two for Cb and Cr,and one additional for joint Cb-Cr when sps_joint_cbcr_enabled_flag isequal to 1, are signalled in the SPS. When same_qp_table_for_chroma isnot present in the bitstream, the value of same_qp_table_for_chroma isinferred to be equal to 1.qp_table_start_minus26[i] plus 26 specifies the starting luma and chromaQP used to describe the i-th chroma QP mapping table. The value ofqp_table_start_minus26[i] shall be in the range of −26−QpBdOffset to 36inclusive. When qp_table_start_minus26[i] is not present in thebitstream, the value of qp_table_start_minus26[i] is inferred to beequal to 0.num_points_in_qp_table_minus1[i] plus 1 specifies the number of pointsused to describe the i-th chroma QP mapping table. The value ofnum_points_in_qp_table_minus1[i] shall be in the range of 0 to63+QpBdOffset, inclusive. When num_points_in_qp_table_minus1[0] is notpresent in the bitstream, the value of num_points_in_qp_table_minus1[0]is inferred to be equal to 0.delta_qp_in_val_minus1[i][j] specifies a delta value used to derive theinput coordinate of the j-th pivot point of the i-th chroma QP mappingtable. When delta_qp_in_val_minus1[0][j] is not present in thebitstream, the value of delta_qp_in_val_minus1[0][j] is inferred to beequal to 0.delta_qp_diff_val[i][j] specifies a delta value used to derive theoutput coordinate of the j-th pivot point of the i-th chroma QP mappingtable.The i-th chroma QP mapping table ChromaQpTable[i] for i=0 . . .numQpTables−1 is derived as follows:

qpInVal[ i ][ 0 ] = qp_table_start_minus26[ i ] + 26 qpOutVal[ i ][ 0 ]= qpIn Val[ i ][ 0 ] for( j = 0; j <= num_points_in_qp_table_minus1[ i]; j++ ) {  qpInVal[ i ][ j + 1 ] = qpIn Val[ i ][ j ] +delta_qp_in_val_minus1[ i ][ j ] + 1  qpOutVal[ i ][ j + 1 ] = qpOutVal[i ][ j ] + ( delta_qp_in_val_minus1[ i ][ j ] {circumflex over ( )}delta_qp_diff_val[ i ][ j ] ) } ChromaQpTable[ i ][ qpInVal[ i ][ 0 ] ]= qpOutVal[ i ][ 0 ] for( k = qpIn Val[ i ][ 0 ] − 1; k >= −QpBdOffset;k−− )  ChromaQpTable[ i ][ k ] = Clip3( QpBdOffset, 63, ChromaQpTable[ i][ k + 1 ] − 1 ) for( j = 0; j <= num_points_in_qp_table_minus1[ i ];j++ ) {  sh = ( delta_qp_in_val_minus1[ i ][ j ] + 1 ) >> 1  for( k =qpInVal[ i ][ j ] + 1, m = 1; k <= qpInval[ i ][ j + 1 ]; k++, m++ )  ChromaQpTable[ i ][ k ] = ChromaQpTable[ i ][ qpInVal[ i ][ j ] ] +   ( ( qpOutVal[ i ][j + 1] − qpOutVal[ i ][j ] ) * m + sh ) / (delta_qp_in_val_minus1[ i ][j] + 1 ) } for( k = qpInVal[ i ][num_points_in_qp_table_minus1[ i ] + 1 ] + 1; k <= 63; k++ ) ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset, 63, ChromaQpTable[ i ][ k− 1 ] + 1 )When same_qp_table_for_chroma is equal to 1, ChromaQpTable[1][k] andChromaQpTable[2][k] are set equal to ChromaQpTable[0][k] for k in therange of −QpBdOffset to 63, inclusive.It is a requirement of bitstream conformance that the values ofqpInVal[i][j] and qpOutVal[i][j] shall be in the range of −QpBdOffset to63, inclusive for i in the range of 0 to numQpTables−1, inclusive, and jin the range of 0 to num_points_in_qp_table_minus1[i]+1, inclusive.In the above description, QpBdOffset is derived as:bit_depth_minus8 specifies the bit depth of the samples of the luma andchroma arrays, BitDepth, and the value of the luma and chromaquantization parameter range offset, QpBdOffset, as follows:

BitDepth=8+bit_depth_minus8

QpBdOffset=6*bit_depth_minus8

bit_depth_minus8 shall be in the range of 0 to 8, inclusive.

4. TECHNICAL PROBLEMS SOLVED BY DISCLOSED TECHNICAL SOLUTIONS

The existing designs in the latest VVC draft specification for APS,deblocking, subpicture, and QP delta have the following problems:

-   -   1) Currently, the value of the APS syntax element        scaling_list_chroma_present_flag is constrained based on        ChromaArrayType derived from SPS syntax elements        chroma_format_ide and separate_colour_plane_flag, phrased as        follows:        -   scaling_list_chroma_present_flag shall be equal to 0 when            ChromaArrayType is equal to 0, and shall be equal to 1 when            ChromaArrayType is not equal to 0.        -   Such constraints in the semantics of the APS syntax element            introduce semantics dependencies of APS on SPS, which should            not occur, because since there is no PPS ID or SPS ID in the            APS syntax, an APS may be applied to pictures (or slices of            pictures) that refer to different SPSs, which may be            associated with different values of ChromaArrayType.            -   a. Additionally, similar APS-SPS semantics dependencies                also exist in the semantics of some ALF/CC-ALF APS                syntax elements, phrased as follows:                -   alf_chroma_filter_signal_flag, alf cc                    cb_filter_signal_flag, and                -   alf_cc_cr_filter_signal_flag shall to be equal to 0                    when ChromaArrayType is equal to 0.            -   b. Currently, when an LMCS APS is signalled, the chroma                residual scaling related syntax elements are always                signalled in the LMCS APS syntax structure, regardless                of whether ChromaArrayType is equal to 0 (i.e., there is                no chroma component in the CLVS). This results in                unnecessary signalling of chroma-related syntax                elements.    -   2) It is asserted that the deblocking control mechanism in the        latest VVC text is pretty complicated, not straightforward, and        not easy to understand, and consequently prone to errors. Here        are some example issues we observed:        -   a. According to the current text, even if the deblocking            filter is disabled in the PPS, it can be enabled in the PH            or SH. For example, if pps_deblocking_filter_disabled_flag            is firstly signalled to be equal to 1, and            deblocking_filter_override_enabled_flag is also signalled to            be equal to 1, it indicates that the deblocking filter is            disabled at PPS and it also allows the deblocking filter            enable/disable control being overridden in the PH or SH.            Then dbf_info_in_ph_flag is signalled subsequently and the            PH syntax element ph_deblocking_filter_disabled_flag might            be signalled to be equal to 0 which ultimately enables the            deblocking filter for slices associated with the PH. In such            case, the deblocking is eventually enabled at PH regardless            that it has been disabled at the higher level (e.g., PPS).            Such design logic is unique in VVC text, and it is quite            different from the design logic of other coding tools (e.g.,            ALF, SAO, LMCS, TMVP, WP, and etc.) as normally when a            coding tool is disabled at a higher layer (e.g., SPS, PPS),            then it is disabled completely at lower layers (e.g., PH,            SH).        -   b. Furthermore, the current definition of            pps_deblocking_filter_disabled_flag is like            “pps_deblocking_filter_disabled_flag equal to 1 specifies            that the operation of deblocking filter is not applied for            slices referring to the PPS in which            slice_deblocking_filter_disabled_flag is not present . . .            ”. However, according to the current syntax table, even            though pps_deblocking_filter_disabled_flag is equal to 1 and            slice_deblocking_filter_disabled_flag is not present, the            operation of deblocking filter would still be applied in            case of ph_deblocking_filter_disabled_flag is present and            signalled to be equal to 0. Therefore, the current            definition of pps_deblocking_filter_disabled_flag is not            correct.        -   c. Moreover, according to the current text, if both the PPS            syntax elements deblocking_filter_override_enabled_flag and            pps_deblocking_filter_disabled_flag are equal to 1, it            specifies that deblocking is disabled in PPS and the control            of deblocking filter is intended to be overridden in the PH            or SH. However, the subsequent PH syntax elements            ph_deblocking_filter_override_flag and            ph_deblocking_filter_disabled_flag might be still signalled            to be equal to 1, which turns out that the resulted            overriding process doesn't change anything (e.g., deblocking            remains disabled in the PH/SH) but just use unnecessary bits            for meaningless signalling.        -   d. In addition, according to the current text, when the SH            syntax element slice_deblocking_filter_override_flag is not            present, it is inferred to be equal to            ph_deblocking_filter_override_flag. However, besides            implicit or explicit signalling in the PPS, the deblocking            parameters can only be signalled either in PH or SH            according to dbf_info_in_ph_flag, but never both. Therefore,            when dbf_info_in_ph_flag is true, the intention is to allow            to signal the overriding deblocking filter parameters in the            PH. In this case, if the PH override flag is true and the SH            override flag is not signalled but inferred to be equal to            the PH override flag, additional deblocking filter            parameters will still be signalled in the SH which is            conflicting with the intention.        -   e. In addition, there is no SPS-level deblocking on/off            control, which may be added and the related syntax elements            in PPS/PH/SH may be updated accordingly.    -   3) Currently, when the PPS syntax element        single_slice_per_subpic_flag is not present, it is inferred to        be equal to 0. single_slice_per_subpic_flag is not present in        two cases: i) no_pic_partition_flag is equal to 1, and ii)        no_pic_partition_flag is equal to 0 and rect_slice_flag is equal        to 0.        -   For case i), no_pic_partition_flag equal to 1 specifies that            no picture partitioning is applied to each picture referring            to the PPS, therefore, there is only one slice in each            picture, and consequently, there is only one subpicture in            each picture and there is only one slice in each subpicture.            Therefore, in this case single_slice_per_subpic_flag should            be inferred to be equal 1.        -   For case ii), since rect_slice_flag is equal to 0, an            inferred value of single_sliceper_subpic_flag is not needed.    -   4) Currently, luma qp delta in either picture or slice level is        always signalled mandatorily, either in the PH or SH, never        both. Whereas the slice-level chroma QP offset is optionally        signalled in the SH. Such design is somewhat not consistent.        -   a. Additionally, the current semantics of the PPS syntax            element cu_qp_delta_enabled_flag is worded as follows:            cu_qp_delta_enabled_flag equal to 1 specifies that the            ph_cu_qp_delta_subdiv_intra_slice and            ph_cu_qp_delta_subdiv_inter_slice syntax elements are            present in PHs referring to the PPS and cu_qpdelta abs may            be present in the transform unit syntax . . . However,            cu_qp_delta_abs may be also present in the palette coding            syntax, which should also be specified by            cu_qp_delta_enabled_flag. In other words, the current            semantics of cu_qp_delta_enabled_flag is not clear enough            and a bit confusing.    -   5) The current design of chroma Qp mapping table is not        straightforward to represent the case of chroma Qp equal to luma        Qp.    -   6) Currently, the subpic_treated_as_pic_flag[i] is inferred to        be equal to the value of sps_independent_subpics_flag. However,        the current spec only allows the horizontal wrap-around to be        enabled when subpic_treated_as_pic_flag[i] is equal to 0,        wherein the wrap-around motion compensation is designed for 360        video content. Therefore, when a pictures contains only one        subpicture (especially for the case that a complete 360 video        sequence contains only one subpicture), the inferred value for        subpic_treated_as_pic_flag[i] may be inferred to be equal to 0        or a certain value that allows the wrap-around motion        compensation.

5. A LISTING OF SOLUTIONS AND EMBODIMENTS

To solve the above problems and some other problems not mentioned,methods as summarized below are disclosed. The items listed below shouldbe considered as examples to explain the general concepts and should notbe interpreted in a narrow way. Furthermore, these items can be appliedindividually or combined in any manner.

In the following discussion, an SH may be associated with a PH, i.e.,the SH is associated with a slice, which is in the picture associatedwith the PH. An SH may be associated with a PPS, i.e., the SH isassociated with a slice, which is in the picture associated with thePPS. A PH may be associated with a PPS, i.e., the PH is associated witha picture, which is associated with the PPS.

In the following discussion, a SPS may be associated with a PPS, i.e.,the PPS may refer to the SPS.

In the following discussion, the changed texts are based on the latestVVC text in JVET-Q2001-vE. Most relevant parts that have been added ormodified are

, and some of the deleted parts are marked with the double bracket(e.g., [[a]] denotes the deletion of the character ‘a’).

-   -   1. Regarding the constraints on APS syntax elements for solving        the first problem, one or more of the following approaches are        disclosed:        -   a. In one example, constrain the value of            scaling_list_chroma_present_flag according to            ChromaArrayType derived by the PH syntax element.            -   i. For example, whether the value of                scaling_list_chroma_present_flag is constrained or not                may be dependent on whether ph_scaling_list_aps_id is                present or not, e.g., as in the first set of                embodiments.                -   1) In one example, it is required that, when                    ph_scaling_list_aps_id is present, the value of                    scaling_list_chroma_present_flag of the APS NAL unit                    having aps_params_type equal to SCALING_APS and                    adaptation_parameter_set_id equal to                    ph_scaling_list_aps_id shall be equal to                    ChromaArrayType==0? 0: 1.            -   ii. Alternatively, scaling_list_chroma_present_flag is                constrained based on ChromaArrayType derived by the PH                syntax elements, but regardless of the presence of                ph_scaling_list_aps_id, e.g., as in the first set of                embodiments.                -   1) In one example, it is required that, the value of                    scaling_list_chroma_present_flag of the APS NAL unit                    having aps_params_type equal to SCALING_APS shall be                    equal to ChromaArrayType==0? 0: 1.        -   b. In one example, constrain the value of lmcs_delta_abs_crs            according to ChromaArrayType derived by the PH syntax            element.            -   i. For example, whether the value of lmcs_delta_abs_crs                is constrained or not may be dependent on whether                ph_lmcs_aps_id is present or not, e.g., as in the first                set of embodiments.                -   1) For example, it is required that, when                    ph_lmcs_aps_id is present, the value of                    lmcs_delta_abs_crs of the APS NAL unit having                    aps_params_type equal to LMCS_APS and                    adaptation_parameter_set_id equal to ph_lmcs_aps_id                    shall be equal to 0 if ChromaArrayType is equal to 0                    and shall be greater than 0 otherwise.                -   2) Alternatively, it is required that, when                    ph_lmcs_aps_id is present, the value of                    lmcs_delta_abs_crs of the APS NAL unit having                    aps_params_type equal to LMCS_APS and                    adaptation_parameter_set_id equal to ph_lmcs_aps_id                    shall be equal to 0 if ChromaArrayType is equal to                    0.            -   ii. Alternatively, lmes_delta_abs_crs is constrained                based on ChromaArrayType derived by the PH syntax                elements, but regardless of the presence of                ph_lmcs_aps_id, e.g., as in the first set of                embodiments.                -   1) For example, it is required that, the value of                    lmcs_delta_abs_crs of the APS NAL unit equal to                    ph_lmcs_aps_id shall be equal to 0 if                    ChromaArrayType is equal to 0 and shall be greater                    than 0 otherwise.                -   2) For example, it is required that, the value of                    lmcs_delta_abs_crs of the APS NAL unit equal to                    ph_lmcs_aps_id shall be equal to 0 if                    ChromaArrayType is equal to 0.        -   c. In one example, constrain the value of ALF APS syntax            elements (e.g., alf_chroma_filter_signal_flag,            alf_cc_cb_filter_signal_flag, alf_cc_cr_filter_signal_flag,            and etc.) according to ChromaArrayType derived by the PH            syntax elements and/or the SH syntax elements.            -   i. For example, whether the value of                alf_chroma_filter_signal_flag and/or                alf_cc_cb_filter_signal_flag and/or                alf_cc_cr_filter_signal_flag are constrained or not may                be dependent on whether ph_alf_aps_id_luma[i] or                slice_alf_aps_id_luma[i] is present or not and/or                whether ChromaArrayType is equal to 0 or not, e.g., as                in the first set of embodiments.                -   1) For example, it is required that, when                    ph_alf_aps_id_luma[i] is present and ChromaArrayType                    is equal to 0, the values of                    alf_chroma_filter_signal_flag,                    alf_cc_cb_filter_signal_flag, and                    alf_cc_cr_filter_signal_flag of the APS NAL unit                    having aps_params_type equal to ALF_APS and                    adaptation_parameter_set_id equal to                    ph_alf_aps_id_luma[i] shall all be equal to 0.                -   2) Additionally, it is required that, when                    slice_alf_aps_id_luma[i] is present and                    ChromaArrayType is equal to 0, the values of                    alf_chroma_filter_signal_flag,                    alf_cc_cb_filter_signal_flag, and                    alf_cc_cr_filter_signal_flag of the APS NAL unit                    having aps_params_type equal to ALF_APS and                    adaptation_parameter_set_id equal to                    slice_alf_aps_id_luma[i] shall all be equal to 0.            -   ii. Altenatively, alf_chroma_filter_signal_flag and/or                alf_cc_cb_filter_signal_flag and/or                alf_cc_cr_filter_signal_flag are constrained based on                ChromaArrayType derived by the PH syntax elements or SH                syntax elements, but regardless of the presence of                ph_alf_aps_id_luma[i] and/or slice_alf_aps_id_luma[i],                e.g., as in the first set of embodiments.                -   1) For example, it is required that, when                    ChromaArrayType is equal to 0, the values of                    alf_chroma_filter_signal_flag,                    alf_cc_cb_filter_signal_flag, and                    alf_cc_cr_filter_signal_flag of the APS NAL unit                    having aps_params_type equal to ALF_APS shall all be                    equal to 0.                -   2) Additionally, it is required that, when                    ChromaArrayType is equal to 0, the values of                    alf_chroma_filter_signal_flag,                    alf_cc_cb_filter_signal_flag, and                    alf_cc_cr_filter_signal_flag of the APS NAL unit                    having aps_params_type equal to ALF_APS shall all be                    equal to 0.            -   iii. Altenatively, alf_chroma_filter_signal_flag and/or                alf_cc_cb_filter_signal_flag and/or                alf_cc_cr_filter_signal_flag are constrained based on                ChromaArrayType derived by the chroma APS ID related PH                or SH syntax elements, e.g., as in the first set of                embodiments.                -   1) For example, alf_chroma_filter_signal_flag is                    constrained according to ChromaArrayType derived by                    the PH syntax element ph_alf_aps_id_chroma and/or                    the SH syntax element slice_alf_aps_id_chroma.                -   2) For example, alf_cc_cb_filter_signal_flag is                    constrained according to ChromaArrayType derived by                    the PH syntax element ph_cc_alf_cb_aps_id and/or the                    SH syntax element slice_cc_alf_cb_aps_id.                -   3) For example, alf_cc_cr_filter_signal_flag is                    constrained according to ChromaArrayType derived by                    the PH syntax element ph_cr_alf_cb_aps_id and/or the                    SH syntax element slice_cr_alf_cb_aps_id.        -   d. In one example, the semantics of APS syntax elements in            the ALF and/or SCALING LIST and/or LMCS data syntax            structure may be not dependent on whether it is 4:0:0 video            coding and/or separate color plane coding.            -   i. For example, the semantics of APS syntax elements in                the ALF data syntax structure (e.g.,                alf_chroma_filter_signal_flag,                alf_cc_cb_filter_signal_flag,                alf_cc_cr_filter_signal_flag, and etc.) may be not                dependent on variables/syntaxes derived by SPS/PH/SH                syntax elements (e.g., ChromaArrayType), e.g., as in the                first set of embodiments.            -   ii. Additionally, alternatively, the semantics of APS                syntax elements in the SCALING LIST data syntax                structure (e.g., scaling_list_chroma_present_flag, and                etc.) may be not dependent on variables/syntaxes derived                by SPS/PH/SH syntax elements (e.g., ChromaArrayType),                e.g., as in the first set of embodiments.        -   e. Additionally, whether the temporalld of the            ALF/SCALING/LMCS APS NAL unit is constrained or not may be            dependent on whether the corresonding APS ID is present or            not, e.g., as in the first set of embodiments.            -   i. For example, whether the temporalld of the ALF APS                NAL unit is constrained or not may be dependent on                whether ph_alf_aps_id_luma[i] and/or                ph_alf_aps_id_chroma and/or ph_cc_alf_cb_aps_id and/or                ph_cc_alf_cr_aps_id is present or not.            -   ii. For example, whether the temporalld of the LMCS APS                NAL unit is constrained or not may be dependent on                whether ph_lmcs_aps_id is present or not.            -   iii. For example, whether the temporalld of the SCALING                APS NAL unit is constrained or not may be dependent on                whether ph_scaling_list_aps_id is present or not.        -   f. Additionally, whether the values of            alf_luma_filter_signal_flag, alf_chroma_filter_signal_flag            and/or alf_cc_cb_filter_signal_flag and/or            alf_cc_cr_filter_signal_flag shall be equal to 1 may be            dependent on whether the corresponding APS ID is present or            not, e.g., as in the first set of embodiments.            -   i. For example, whether alf_luma_filter_signal_flag                shall be equal to 1 or not may be dependent on whether                ph_alf_aps_id_luma[i] and/or slice_alf_aps_id_luma[i] is                present or not.            -   ii. For example, whether alf_chroma_filter_signal_flag                shall be equal to 1 or not may be dependent on whether                ph_alf_aps_id_chroma and/or slice_alf_aps_id_chroma is                present or not.            -   iii. For example, whether alf_cc_cb_filter_signal_flag                shall be equal to 1 or not may be dependent on whether                ph_cc_alf_cb_aps_id and/or slice_cc_alf_cb_aps_id is                present or not.            -   iv. For example, whether alf_cc_cr_filter_signal_flag                shall be equal to 1 or not may be dependent on whether                ph_cc_alf_cr_aps_id and/or slice_cc_alf_cr_aps_id is                present or not.        -   g. Additionally, alternatively, whether the chroma ALF APS            ID syntax elements in the SH (e.g., slice_alf_aps_id_chroma,            slice_cc_alf_cb_aps_id, slice_cr_alf_cb_aps_id, and etc.) in            inferred or not may be dependent on the value of            ChromaArrayType, e.g., as in the first set of embodiments.            -   i. For example, when ChromaArrayType is not equal to 0,                the value of the chroma ALF APS ID syntax elements in                the SH (e.g., slice_alf_aps_id_chroma,                slice_cc_alf_cb_aps_id, slice_cr_alf_cb_aps_id, and                etc.) may be inferred.    -   2. Regarding the signalling of deblocking control for solving        the second problem, one or more of the following approaches are        disclosed, e.g., as in the second set of embodiments:        -   a. In one example, an N-bit (such as N=2) deblocking mode            indicator (e.g., named deblocking_filter_mode_idc) is            signalled.            -   i. In one example, the syntax element                deblocking_filter_mode_idc is u(2) coded.                -   a) Alternatively, the parsing process of                    deblocking_filter_mode_idc is unsigned integer with                    N (such as N=2) bits.            -   ii. In one example, the syntax element                deblocking_filter_mode_idc is signalled in the PPS.            -   iii. In one example, the syntax element                deblocking_filter_mode_idc is used to specify the                following four modes: a) deblocking fully disabled and                not used for all slices; b) deblocking used for all                slices using 0-valued p and tC offsets; c) deblocking                used for all slices using p and tC offsets explicitly                signalled in the PPS; and d) deblocking further                controlled at either picture or slice level.        -   b. A syntax flag ph/slice_deblocking_filter_used_flag is            signalled either in the PH or SH, specifying whether            deblocking is used for the current picture/slice.        -   c. A syntax flag            ph/slice_deblocking_parameters_override_flag is signalled            either in the PH or SH, specifying whether the R and tC            offsets are overridden by the values signalled in the PH/SH.            -   i. Additionally, infer the value of                slice_deblocking_parameters_override_flag to be equal to                0 when not present.        -   d. In one example, the syntax elements specifying the            deblocking control (e.g., enable flag, disable flag, control            flag, deblocking mode indicator, deblocking filter beta/tc            parameters, and etc.) may be signalled in the SPS.            -   i. In one example, one or more syntax elements may be                signalled in the SPS specifying whether the deblocking                is enabled or not in the video unit (e.g., CLVS).            -   ii. Additionally, when the deblocking is disabled in the                SPS, it is required that the syntax element in the                PPS/PH/SH regarding the deblocking on/off control at                PPS/PH/SH level shall be equal to a certain value that                specifying the deblocking is fully disabled and not used                for all slices.            -   iii. In one example, the deblocking filter control                present flag may be signalled in the SPS.            -   iv. For example, an N-bit (such as N=2) deblocking mode                indicator (e.g., named deblocking_filter_mode_idc) may                be signalled in the SPS.            -   v. For example, beta/tc deblocking parameters may be                signalled in the SPS.            -   vi. For example, whether the deblocking is enabled with                0-valued beta/tc deblocking parameters may be dependent                on the SPS syntax element.            -   vii. For example, the deblocking may be applied at the                SPS/PPS/PH/SH level and use the beta/tc deblocking                parameters signalled in the SPS.            -   viii. For example, the deblocking may be applied at the                SPS/PPS/PH/SH level and use the 0-valued deblocking                parameters signalled in the SPS.    -   3. Regarding the inference of the PPS syntax element        single_slice_per_subpic_flag for solving the third problem, one        or more of the following approaches are disclosed:        -   a. In one example, infer single_slice_per_subpic_flag to be            equal to 1 when no_pic_partition_flag is equal to 1, e.g.,            the semantics of single_slice_per_subpic_flag is changed as            follows:            -   single_slice_per_subpic_flag equal to 1 specifies that                each subpicture consists of one and only one rectangular                slice. single_slice_per_subpic_fla equal to 0 specifies                that each subpicture may consist of one or more                rectangular slices. When                [[not present]], the value of                single_slice_per_subpic_flag is inferred to be equal to                [[0]]    -   4. Regarding the picture or slice QP delta signalling for        solving the fourth problem, one or more of the following        approaches are disclosed:        -   a. In one example, picture or slice level chroma QP offset            are always signalled, either in the PH or SH.            -   i. For example, if there is chroma component in the                video content (e.g., ChromaArrayType is not equal to 0),                picture or slice level chroma QP offset may be always                signalled, without conditioned on the present flag                signalled in the PPS (e.g.,                pps_slice_chroma_qp_offsets_present_flag).            -   ii. Alternatively, if there is chroma component in the                video content (e.g., ChromaArrayType is not equal to 0),                slice_cb_qp_offset and slice_cr_qp_offset syntax                elements may be always present in the associated slice                headers, regardless the PPS present flag (e.g.,                pps_slice_chroma_qp_offsets_present_flag).            -   iii. Additionally, the present flag (e.g.,                pps_slice_chroma_qp_offsets_present_flag) specifying the                presence of slice_cb_qp_offset and slice_cr_qp_offset                syntax elements, may be not signalled.        -   b. In one example, pps_cu_qp_delta_enabled_flag may be used            to specify the presence of cu_qp_delta_abs and            cu_qp_delta_sign_flag in both the transform unit syntax and            the palette coding syntax, and the semantics of            pps_cu_qp_delta_enabled_flag are changed as follows:            -   _cu_qp_delta_enabled_flag equal to 1 specifies that the                ph_cu_qp_delta_subdiv_intra_slice and                ph_cu_qp_delta_subdiv_inter_slice syntax elements are                present in PHs referring to the PPS, and                cu_qp_delta_abs                may be present in the transform unit syntax                , pps_cu_qp_delta_enabled_flag equal to 0 specifies that                the ph_cu_qp_delta_subdiv_intra_slice and                ph_cu_qp_delta_subdiv_inter_slice syntax elements are                not present in PHs referring to the PPS, and                cu_qp_delta_abs                [[is]] not present in the transform unit syntax        -   c. In one exam the luma QP delta may be signalled in both            the PH and the SH.            -   i. For example, luma QP delta present flag may be                signalled in the PPS and/or PH, and/or the SH.            -   ii. For example, whether the luma QP delta is signalled                in PH/SH is dependent on the present flags in the PPS                and/or PH/SH.            -   iii. For example, the values of the PH luma QP delta and                the SH luma QP delta may be additive and used for                calculating the luma quantization parameter such as                SliceQp_(Y).        -   d. In one example, the chroma QP offsets may be signalled in            both the PH and the SH.            -   i. For example, chroma QP offsets present flag may be                signalled in the PPS and/or PH, and/or the SH.            -   ii. For example, whether the chroma QP offsets are                signalled in PH/SH is dependent on the present flags in                the PPS and/or PH/SH.            -   iii. For example, the values of the PH chroma QP offsets                and the SH chroma QP offsets may be additive and used                for deriving the chroma quantization parameter for the                Cb and Cr components.    -   5. Regarding the chroma Qp mapping tables, one or more of the        following approaches are disclosed:        -   a. In one example, in the derivation process of the chroma            QP table, the XOR operator should be performed between            (delta_qp_in_val_minus1[i][j]+1) and            delta_qp_diff_val[i][j], e.g. as in the third set of            embodiment.        -   b. It is proposed to have a flag in            sps_multiple_sets_of_chroma_qp_table_present_flag in SPS.            -   i. When sps_multiple_sets_of                chroma_qp_table_present_flag is equal to 0, only one set                of chroma Qp mapping table is allowed to be signalled.            -   ii. When sps_multiple_sets_of                chroma_qp_table_present_flag is equal to 1, more than                one set of chroma Qp mapping table are allowed to be                signalled.        -   c. More than one set of chroma Qp mapping tables may be            disallowed to be signalled for a sequence without B/P            slices.    -   6. Regarding the sps_independent_subpics_flag and        subpic_treated_as_pic_flag[i] for solving the sixth problem, one        or more of the following approaches are disclosed:        -   a. In one example, the presence of            sps_independent_subpics_flag is dependent on whether the            number of subpictures is greater than 1.            -   i. For example, only when the number of subpictures is                greater than 1 (e.g., if (sps_num_subpics_minus1>0)),                sps_independent_subpics_flag is signalled.            -   ii. For example, when the number of subpictures is equal                to 1 (e.g., if (sps_num_subpics_minus1==0)), then the                signalling of sps_independent_subpics_flag is skipped.        -   b. Additionally, when sps_independent_subpics_flag is not            present, it is inferred to be equal to a certain value (such            as 0 or 1).        -   c. In one example, when subpic_treated_as_pic_flag[i] is not            present, it is inferred to be equal to a certain value (such            as 0 or 1).        -   d. In one example, when subpic_treated_as_pic_flag[i] is not            present, it is inferred to be equal to a certain value            wherein the wrap-around motion compensation is enabled (or            may be used).            -   i. Additionally, when subpic_treated_as_pic_flag[i] is                not present, it is inferred to be equal to a certain                value wherein the horizontal wrap-around motion                compensation is enabled (or may be used).        -   e. In one example, the inferred value of            subpic_treated_as_pic_flag[i] may be dependent on whether a            picture only consists of one subpicture; and/or whether the            subpicture has the same width as the picture.            -   i. In one example, if the subpicture has the same width                as the picture, subpic_treated_as_pic_flag[i] may be                inferred to X (e.g., X=0).        -   f. In one example, when sps_independent_subpics_flag is not            present, what value that sps_independent_subpics_flag is            inferred to may be dependent on other syntax element(s) or            variable(s).            -   i. For example, the inferred value may depend on whether                the subpicture information is present or not (e.g.,                subpic_info_present_flag is equal to 0 or 1).            -   ii. For example, when subpic_info_present_flag is equal                to 0 and sps_independent_subpics_flag is not present, it                is inferred to be equal to a certain value (such as 0 or                1).            -   iii. For example, when subpic_info_present_flag is equal                to 1 and sps_independent_subpics_flag is not present, it                is inferred to be equal to a certain value (such as 0 or                1).        -   g. In one example, when subpic_treated_as_pic_flag[i] is not            present, what value that subpic_treated_as_pic_flag[i] is            inferred to may be dependent on the presence of subpicture            information (e.g., subpic_info_present_flag) and/or the            number of subpictures in the CLVS (e.g.,            sps_num_subpics_minus1) and/or sps_independent_subpics_flag.            -   i. In one example, when subpic_info_present_flag is                equal to 0, and subpic_treated_as_pic_flag[i] is not                present, the value of subpic_treated_as_pic_flag[i] is                inferred to be equal to a certain value (such as 0).            -   ii. In one example, when subpic_info_present_flag is                equal to 1, and subpic_treated_as_pic_flag[i] is not                present, the value of subpic_treated_as_pic_flag[i] is                inferred to be equal to a certain value (such as 1).            -   iii. In one example, when subpic_info_present_flag is                equal to 1, and sps_num_subpics_minus1 is equal to 0,                and subpic_treated_as_pic_flag[i] is not present, the                value of subpic_treated_as_pic_flag[i] is inferred to be                equal to a certain value (such as 0 or 1).            -   iv. In one example, when subpic_info_present_flag is                equal to 1, sps_num_subpics_minus1 is greater than 0,                sps_independent_subpics_flag is equal to 1, and                subpic_treated_as_pic_flag[i] is not present, the value                of subpic_treated_as_pic_flag[i] is inferred to be equal                to a certain value (such as 0 or 1).    -   7. How to do padding or clipping on a boundary during the        inter-prediction process may depend on a combined checking of        the type of boundary, the indication of wrap around padding or        clipping (e.g. pps_ref_wraparound_enabled_flag,        sps_ref_wraparound_enabled_flag, and etc.) and the indication of        treating subpicture boundary as picture boundary (e.g.        subpic_treated_as_pic_flag[i]).        -   a. For example, if a boundary is a picture boundary, the            indication of wrap around padding is true, wrap around            padding (or wrap around clipping) may be applied, without            considering the indication of treating subpicture boundary            as picture boundary.            -   i. In one example, the boundary must be a vertical                boundary.        -   b. For example, if both two vertical boundaries are picture            boundaries, the indication of wrap around padding is true,            wrap around padding (or wrap around clipping) may be            applied, without considering the indication of treating            subpicture boundary as picture boundary.        -   c. In one example, the above wrap around padding (or wrap            around clipping) may indicate horizontal wrap-around            padding/clipping.    -   8. In one example, different indications for wrap around padding        or clipping may be signaled for different subpictures.    -   9. In one example, different offsets for wrap around padding or        clipping may be signaled for different subpictures.    -   10. In the PH/SH, a variable X is used to indicate whether B        slice is allowed/used in a picture/slice, and the variable may        be derived using one of the following ways: a)        (rpl_info_in_ph_flag && num_ref_entries[0][RplsIdx[0]]>0 &&        num_ref_entries[1][RplsIdx[1]]>0); b) (rpl_info_in_ph_flag &&        num_ref_entries[1][RplsIdx[1]]>0); c) (rpl_info_in_ph_flag &&        num_ref_entries[1][RplsIdx[1]]>1); d) (rpl_info_in_ph_flag &&        num_ref_entries[1][RplsIdx[1]]>0); e) based on NumRefIdxActive        (e.g., NumRefIdxActive for list 1 greater than K (e.g., K=0)) in        the VVC text; f) based on number of allowed reference pictures        for list 1.        -   1) Alternatively, furthermore, signalling and/or semantics            and/or inference of one or multiple syntax elements            signalled in PH may be modified according to the variable.            -   i. In one example, the one or multiple syntax elements                are those for enabling a coding tool which requires more                than one prediction signal, such as bi-prediction or                mixed intra and inter coding, or prediction with                linear/non-linear weighting from multiple prediction                blocks.            -   ii. In one example, the one or multiple syntax elements                may include, but not limited to:                -   a) ph_collocated_from_l0_flag                -   b) mvd_11_zero_flag                -   c) ph_disable_bdof_flag                -   d) ph_disable_dmvr_flag                -   e) num_11_weights            -   iii. In one example, only when the variable indicates                that the picture may contain one or more B slices, the                one or multiple syntax elements may be signalled.                Otherwise, the signalling is skipped, and the values of                the syntax element are inferred.                -   a) Alternatively, furthermore, whether to signal the                    one or more syntax elements may depend on the                    variable X such as (X being true or 1).                -   b) ph_disable_bdof_flag may be signalled only when                    (sps_bdof_pic_present_flag                    ) is true.                -   c) ph_disable_dmvr_flag may be signalled only when                    (sps_dmvr_pic_present_flag                    ) is true.            -   iv. In one example, when X is equal to 0 (or false),                mvd_11_zero_flag is not signalled, and its values is                inferred to be 1.            -   v. In one example, the inference of the one or multiple                syntax elements are dependent on the value of the                variable X.                -   a) In one example, for the ph_disable_bdof_flag, the                    following applies:                -    If sps_bdof_enabled_flag is equal to 1                    , the value of ph_disable_bdof_flag is inferred to                    be equal to 0.                -    Otherwise (sps_bdof_enabled_flag is equal to 0                    ), the value of ph_disable_bdof_flag is inferred to                    be equal to 1                -   b) In one example, for the ph_disable_dmvr_flag, the                    following applies:                -    If sps_dmvr_enabled_flag is equal to 1                    , the value of ph_disable_dmvr_flag is inferred to                    be equal to 0.                -    Otherwise (sps_dmvr_enabled_flag is equal to 0                    ), the value of ph_disable_dmvr_flag is inferred to                    be equal to 1.            -   c) In one example, when ph_temporal_mvp_enabled_flag and                rpl_info_in_ph_flag are both equal to 1 and X is equal                to 0 (or false), the value of ph_collocated_from_l0_flag                is inferred to be equal to 1.            -   d) In one example, when X is equal to 0 (or false),                num_l1_weights is not signalled and its value is                inferred to be 0, and, consequently, weighted prediction                parameters for reference picture list 1 are not                signalled in the PH or SHs of the picture.

6. EXAMPLE EMBODIMENTS

Below are some example embodiments for some of the aspects summarizedabove in Section 5, which can be applied to the VVC specification. Thechanged texts are based on the latest VVC text in JVET-Q2001-vE. Mostrelevant parts that have been added or modified are highlighted in

, and some of the deleted parts are marked with the double bracket(e.g., [[a]] denotes the deletion of the character ‘a’).

6.1. First Set of Embodiments

This is a set of embodiments for items 1 summarized above in Section 5.

6.1.1. An Embodiment for 1.a.i

ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of thescaling list APS. The TemporalId of the APS NAL unit havingaps_params_type equal to SCALING_APS and adaptation_parameter_set_idequal to ph_scaling_list_aps_id shall be less than or equal to theTemporalId of the picture associated with PH.

scaling_list_chroma_present_flag equal to 1 specifies that chromascaling lists are present in scaling_list_data( ).scaling_list_chroma_present_flag equal to 0 specifies that chromascaling lists are not present in scaling_list_data( ). [[It is arequirement of bitstream conformance thatscaling_list_chroma_present_flag shall be equal to 0 whenChromaArrayType is equal to 0, and shall be equal to 1 whenChromaArrayType is not equal to 0.]]

6.1.2. An Embodiment for 1.a.ii

ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of thescaling list APS.The TemporalId of the APS NAL unit having aps_params_type equal toSCALING_APS and adaptation_parameter_set_id equal toph_scaling_list_aps_id shall be less than or equal to the TemporalId ofthe picture associated with PH.

(alternatively, it maybe phrased as follows:

.scaling_list_chroma_present_flag equal to 1 specifies that chromascaling lists are present in scaling_list_data( ).scaling_list_chroma_present_flag equal to 0 specifies that chromascaling lists are not present in scaling_list_data( ). [[It is arequirement of bitstream conformance thatscaling_list_chroma_present_flag shall be equal to 0 whenChromaArrayType is equal to 0, and shall be equal to 1 whenChromaArrayType is not equal to 0.]]

6.1.3. An Embodiment for 1.b.i

ph_lmcs_aps_id specifies the adaptation_parameter set_id of the LMCS APSthat the slices associated with the PH refers to.The TemporalId of the APS NAL unit having aps_params_type equal toLMCS_APS and adaptation_parameter_set_id equal to ph_lmcs aps_id shallbe less than or equal to the TemporalId of the picture associated withPH.

6.1.4. An Embodiment for 1.b.ii

ph_lmcs_aps_id specifies the adaptation_parameter set_id of the LMCS APSthat the slices associated with the PH refers to.The TemporalId of the APS NAL unit having aps_params_type equal toLMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shallbe less than or equal to the TemporalId ofthe picture associated withPH.

6.1.5. An Embodiment for 1.c.i

The semantics of PH syntax elements are changes as follows:ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of thei-th ALF APS that the luma component of the slices associated with thePH refers to.The value of alf_luma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto ph_alf_aps_id_luma[i] shall be equal to 1.The TemporalId of the APS NAL unit having aps_params_type equal toALF_APS and adaptation_parameter_set_id equal to ph alf aps_id_luma[i]shall be less than or equal to the TemporalId of the picture associatedwith the PH.

The semantics of SH syntax elements are changes as follows:slice_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id ofthe i-th ALF APS that the luma component of the slice refers to.-Whenslice_alf_enabled flag is equal to 1 and slice_alf_aps_id_luma[i] is notpresent, the value of slice_alf_aps_id_luma[i] is inferred to be equalto the value of ph_alf_aps_id_luma[i].The TemporalId of the APS NAL unit having aps_params_type equal toALF_APS and adaptation_parameter_set_id equal toslice_alf_aps_id_luma[i] shall be less than or equal to the TemporalIdof the coded slice NAL unit.The value of alf_luma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_alf_aps_id_luma[i] shall be equal to 1.

And the semantics of the APS syntax elements in the ALF data syntaxstructure are changed as follows:alf_chroma_filter_signal_flag equal to 1 specifies that a chroma filteris signalled. alf_chroma_filter_signal_flag equal to 0 specifies that achroma filter is not signalled. [[When ChromaArrayType is equal to 0,alf_chroma_filter_signal_flag shall be equal to 0.]]alf_cc_cb_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cb colour component are signalled.alf_cc_cb_filter_signal_flag equal to 0 specifies that cross-componentfilters for Cb colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall beequal to 0.]]alf_cc_cr_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cr colour component are signalled.alf_cc_cr_filter_signal_flag equal to 0 specifies that cross-componentfilters for the Cr colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall beequal to 0.]]

6.1.6. An Embodiment for 1.c.ii

The semantics of PH syntax elements are changes as follows:ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of thei-th ALF APS that the luma component of the slices associated with thePH refers to.The value of alf_luma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto ph_alf_aps_id_luma[i] shall be equal to 1.The TemporalId of the APS NAL unit having aps_params_type equal toALF_APS and adaptation_parameter_set id equal to ph_alf_aps id_luma[i]shall be less than or equal to the TemporalId of the pictures assocaitedwith the PH.

ph_alf_chroma_idc equal to 0 specifies that the adaptive loop filter isnot applied to Cb and Cr colour components. ph_alf_chroma_idc equal to 1indicates that the adaptive loop filter is applied to the Cb colourcomponent. ph_alf_chroma_idc equal to 2 indicates that the adaptive loopfilter is applied to the Cr colour component. ph_alf_chroma_idc equal to3 indicates that the adaptive loop filter is applied to Cb and Cr colourcomponents. When ph_alf_chroma_idc is not present, it is inferred to beequal to 0.The semantics of SH syntax elements are changes as follows:slice_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id ofthe i-th ALF APS that the luma component of the slice refers to.-Whenslice_alf_enabled flag is equal to 1 and slice_alf_aps_id_luma[i] is notpresent, the value of slice_alf_aps_id_luma[i] is inferred to be equalto the value of ph_alf_aps_id_luma[i].The TemporalId of the APS NAL unit having aps_params_type equal toALF_APS and adaptation_parameter_set_id equal toslice_alf_aps_id_luma[i] shall be less than or equal to the TemporalIdof the coded slice NAL unit.The value of alf_luma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation parameter_set_id equalto slice_alf_aps_id_luma[i] shall be equal to 1.

And the semantics of the APS syntax elements in the ALF data syntaxstructure are changed as follows:alf_chroma_filter_signal_flag equal to 1 specifies that a chroma filteris signalled. alf_chroma_filter_signal_flag equal to 0 specifies that achroma filter is not signalled. [[When ChromaArrayType is equal to 0,alf_chroma_filter_signal_flag shall be equal to 0.]]alf_cc_cb_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cb colour component are signalled.alf_cc_cb_filter_signal_flag equal to 0 specifies that cross-componentfilters for Cb colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall beequal to 0.]]alf_cc_cr_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cr colour component are signalled.alf_cc_cr_filter_signal_flag equal to 0 specifies that cross-componentfilters for the Cr colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall beequal to 0.]]

6.1.7. An Embodiment for 1.c.iii

The semantics of PH syntax elements are changes as follows:ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id of theALF APS that the chroma component of the slices associated with the PHrefers to.The value of alf_chroma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter set id e ualto h alf aps_id_chroma shall be equal to 1.

ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of the ALFAPS that the Cb colour component of the slices associated with the PHrefers toThe value of alf_cc_cb_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto ph_cc_alf_cb_aps_id shall be equal to 1.

ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of the ALFAPS that the Cr colour component of the slices associated with the PHrefers to.The value of alf_cc_cr_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto ph_cc_alf_cr_aps_id shall be equal to 1.

The semantics of SH syntax elements are changes as follows:slice_alf_aps_id_chroma specifies the adaptation_parameter_set_id of theALF APS that the chroma component of the slice refers to. The TemporalIdof the APS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_alf_enabled flag is equal to 1 and slice_alf_aps_id_chroma is notpresent, the value of slice_alf_aps_id_chroma is inferred to be equal tothe value of ph_alf_aps_id_chroma.The value of alf_chroma_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_alf_aps_id_chroma shall be equal to 1.

slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id thatthe Cb colour component of the slice refers to.The TemporalId of the APS NAL unit having aps_params_type equal toALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_idshall be less than or equal to the TemporalId of the coded slice NALunit. When slice_cc_alf_cb_enabled flag is equal to 1 andslice_cc_alf_cb_aps_id is not present, the value ofslice_cc_alf_cb_aps_id is inferred to be equal to the value ofph_cc_alf_cb_aps_id.The value of alf_cc_cb_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_cc_alf_cb_aps_id shall be equal to 1.

slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id thatthe Cr colour component of the slice refers to. The TemporalId of theAPS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id isnot present, the value of slice_cc_alf_cr_aps_id is inferred to be equalto the value of ph_cc_alf_cr_aps_id.The value of alf_cc_cr_filter_signal_flag of the APS NAL unit havingaps_params_type equal to ALF_APS and adaptation_parameter_set_id equalto slice_cc_alf_cr_aps_id shall be equal to 1.

And the semantics of APS syntax elements are changed as follows:alf_chroma_filter_signal_flag equal to 1 specifies that a chroma filteris signalled. alf_chroma_filter_signal_flag equal to 0 specifies that achroma filter is not signalled. [[When ChromaArrayType is equal to 0,alf_chroma_filter_signal_flag shall be equal to 0.]]alf_cc_cb_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cb colour component are signalled.alf_cc_cb_filter_signal_flag equal to 0 specifies that cross-componentfilters for Cb colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall beequal to 0.]]alf_cc_cr_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cr colour component are signalled.alf_cc_cr_filter_signal_flag equal to 0 specifies that cross-componentfilters for the Cr colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall beequal to 0.]]

6.1.8. An Embodiment for 1.d.i

The semantics of APS syntax elements in the ALF data syntax structureare changed as follows:alf_chroma_filter_signal_flag equal to 1 specifies that a chroma filteris signalled. alf_chroma_filter_signal_flag equal to 0 specifies that achroma filter is not signalled. [[When ChromaArrayType is equal to 0,alf_chroma_filter_signal_flag shall be equal to 0.]]alf_cc_cb_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cb colour component are signalled.alf_cc_cb_filter_signal_flag equal to 0 specifies that cross-componentfilters for Cb colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall beequal to 0.]]alf_cc_cr_filter_signal_flag equal to 1 specifies that cross-componentfilters for the Cr colour component are signalled.alf_cc_cr_filter_signal_flag equal to 0 specifies that cross-componentfilters for the Cr colour component are not signalled. [[WhenChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall beequal to 0.]]

6.1.9. An Embodiment for 1.d.ii

The semantics of APS syntax elements in the SCALING LIST data syntaxstructure are changed as follows: scaling_list_chroma_present_flag equalto 1 specifies that chroma scaling lists are present inscaling_list_data( ). scaling_list_chroma_present_flag equal to 0specifies that chroma scaling lists are not present inscaling_list_data( ). [[It is a requirement of bitstream conformancethat scaling_list_chroma_present_flag shall be equal to 0 whenChromaArrayType is equal to 0, and shall be equal to 1 whenChromaArrayType is not equal to 0 . . . .]]

6.1.10. An Embodiment for i.e and 1.f

ph scaling list aps id specifies the adaptation_parameter_set_id of thescaling list APS.

-   -   The TemporalId of the APS NAL unit having aps_params_type equal        to SCALING_APS and adaptation_parameter_set_id equal to        ph_scaling_list_aps_id shall be less than or equal to the        TemporalId of the picture associated with PH.        ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the        LMCS APS that the slices associated with the PH refers to.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to LMCS_APS and adaptation_parameter_set_id equal to        ph_lmcs_aps_id shall be less than or equal to the TemporalId of        the picture associated with PH.        ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id        of the i-th ALF APS that the luma component of the slices        associated with the PH refers to.    -   The value of alf_luma_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall        be equal to 1.    -   The TemporalId of the APS NAL unit having aps_pamms_type equal        to ALF_APS and adaptation_parameter_set id equal to        ph_alf_aps_id_luma[i] shall be less than or equal to the        TemporalId of the picture associated with the PH.        ph_alf_chroma_idc equal to 0 specifies that the adaptive loop        filter is not applied to Cb and Cr colour components.        ph_alf_chroma_idc equal to 1 indicates that the adaptive loop        filter is applied to the Cb colour component. ph_alf_chroma_idc        equal to 2 indicates that the adaptive loop filter is applied to        the Cr colour component. ph_alf_chroma_idc equal to 3 indicates        that the adaptive loop filter is applied to Cb and Cr colour        components. When ph_alf_chroma_idc is not present, it is        inferred to be equal to 0.        ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id        of the ALF APS that the chroma component of the slices        associated with the PH refers to.    -   The value of alf_chroma_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_alf_aps_id_chroma shall        be equal to 1.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        ph_alf_aps_id_chroma shall be less than or equal to the        TemporalId of the picture associated with the PH.        ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of        the ALF APS that the Cb colour component of the slices        associated with the PH refers to.    -   The value of alf_cc_cb_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id shall        be equal to 1.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        ph_cc_alf_cb_aps_id shall be less than or equal to the        TemporalId of the picture associated with the PH.        ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of        the ALF APS that the Cr colour component of the slices        associated with the PH refers to.    -   The value of alf_cc_cr_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id shall        be equal to 1.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        ph_cc_alf_cr_aps_id shall be less than or equal to the        TemporalId of the picture associated with the PH.        slice_alf_aps_id_luma[i] specifies the        adaptation_parameter_set_id of the i-th ALF APS that the luma        component of the slice refers to.-When slice_alf_enabled_flag is        equal to 1 and slice_alf_aps_id_luma[i] is not present, the        value of slice_alf_aps_id_luma[i] is inferred to be equal to the        value of ph_alf_aps_id_luma[i].    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        slice_alf_aps_id_luma[i] shall be less than or equal to the        TemporalId of the coded slice NAL unit.    -   The value of alf_luma_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i]        shall be equal to 1.        slice_alf_aps_id_chroma specifies the        adaptation_parameter_set_id of the ALF APS that the chroma        component of the slice refers to. When slice_alf_enabled flag is        equal to 1 and slice_alf_aps_id_chroma is not present, the value        of slice_alf_aps_id_chroma is inferred to be equal to the value        of ph_alf_aps_id_chroma.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        slice_alf_aps_id_chroma shall be less than or equal to the        TemporalId of the coded slice NAL unit.    -   The value of alf_chroma_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to slice_alf_aps_id_chroma        shall be equal to 1.        slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id        that the Cb colour component of the slice refers to.        When slice_cc_alf_cb_enabled flag is equal to 1 and        slice_cc_alf_cb_aps_id is not present, the value of        slice_cc_alf_cb_aps_id is inferred to be equal to the value of        ph_cc_alf_cb_aps_id.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        slice_cc_alf_cb_aps_id shall be less than or equal to the        TemporalId of the coded slice NAL unit.    -   The value of alf_cc_cb_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id        shall be equal to 1.        slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id        that the Cr colour component of the slice refers to. When        slice_cc_alf_cr_enabled_flag is equal to 1 and        slice_cc_alf_cr_aps_id is not present, the value of        slice_cc_alf_cr_aps_id is inferred to be equal to the value of        ph_cc_alf_cr_aps_id.    -   The TemporalId of the APS NAL unit having aps_params_type equal        to ALF_APS and adaptation_parameter_set_id equal to        slice_cc_alf_cr_aps_id shall be less than or equal to the        TemporalId of the coded slice NAL unit.    -   The value of alf_cc_cr_filter_signal_flag of the APS NAL unit        having aps_params_type equal to ALF_APS and        adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id        shall be equal to 1.

6.1.11. An Embodiment for 1.g

The semantics of SH syntax elements are changes as follows:slice_alf_aps_id_chroma specifies the adaptation_parameter_set_id of theALF APS that the chroma component of the slice refers to. The TemporalIdof the APS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_alf_enabled flag is equal to 1 and slice_alf_aps_id_chroma is notpresent and

, the value of slice_alf_aps_id_chroma is inferred to be equal to thevalue of ph_alf_aps_id_chroma.slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id thatthe Cb colour component of the slice refers to.The TemporalId of the APS NAL unit having aps_params_type equal toALF_APS andadaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_cc_alf_cb_enabled_flag is equal to 1 and slice_cc_alf_cb_aps_id isnot present and ChromaArrayType is not equal to 0, the value ofslice_cc_alf_cb_aps_id is inferred to be equal to the value ofph_cc_alf_cb_aps_id.slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id thatthe Cr colour component of the slice refers to. The TemporalId of theAPS NAL unit having aps_params_type equal to ALF_APS andadaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall beless than or equal to the TemporalId of the coded slice NAL unit. Whenslice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id isnot present and ChromaArrayType is not equal to 0, the value ofslice_cc_aif_cr_aps_id is inferred to be equal to the value ofph_cc_alf_cr_aps_id.

6.2. Second Set of Embodiments

This is a set of embodiments for items 2 (from 2.a to 2.c) summarizedabove in Section 5.The syntax structure pic_parameter_set_rbsp( ) is changed as follows:

Descriptor pic_parameter_set_rbsp( ) {  pps_pic_parameter_set_id ue(v)...  deblocking_filter_[[control_present_flag]]mode_idc u([1]]2) if(deblocking_filter_[[control_present_flag]]mode_idc > 1 ) {  [[deblocking_filter_override_enabled_flag]] [[u(1)]]  [[pps_deblocking_filter_disabled_flag]] [[u(1)]]   [[if(!pps_deblocking_filter_disabled_flag ) { }]    pps_beta_offset_div2se(v)    pps_tc_offset_div2 se(v)    pps_cb_beta_offset_div2 se(v)   pps_cb_tc_offset_div2 se(v)    pps_cr_beta_offset_div2 se(v)   pps_cr_tc_offset_div2 se(v)   [[}]]  }  [[rpl_info_in_ph_flag]][[u(1)]]  if( deblocking_filter_[[override_enabled_ flag]]mode_idc = = 3)   dbf_info_in_ph_flag u(1)  rpl_info_in_ph_flag ...

3

[[deblocking_filter_control_present_flag equal to 1 specifies thepresence of deblocking filter control syntax elements in the PPS.deblocking_filter_control_present_flag equal to 0 specifies the absenceof deblocking filter control syntax elements in the PPS.deblocking_filter_override_enabled_flag equal to 1 specifies thepresence of ph_deblocking_filter_override_flag in the PHs referring tothe PPS or slice_deblocking_filter_override_flag in the slice headersreferring to the PPS. deblocking_filter_override_enabled_flag equal to 0specifies the absence of ph_deblocking_filter_override_flag in PHsreferring to the PPS or slice_deblocking_filter_override_flag in sliceheaders referring to the PPS. When not present, the value ofdeblocking_filter_override_enabled_flag is inferred to be equal to 0.pps_deblocking_filter_disabled_flag equal to 1 specifies that theoperation of deblocking filter is not applied for slices referring tothe PPS in which slice_deblocking_filter_disabled_flag is not present.pps_deblocking_filter_disabled_flag equal to 0 specifies that theoperation of the deblocking filter is applied for slices referring tothe PPS in which slice_deblocking_filter_disabled_flag is not present.When not present, the value of pps_deblocking_filter_disabled_flag isinferred to be equal to 0.]]dbf_info_in_ph_flag equal to 1 specifies that deblocking filterinformation is present in the PH syntax structure and not present inslice headers referring to the PPS that do not contain a PH syntaxstructure. dbf_info_in_ph_flag equal to 0 specifies that deblockingfilter information is not present in the PH syntax structure and may bepresent in slice headers referring to the PPS that do not contain a PHsyntax structure. [[When not present, the value of dbf_info_in_ph_flagis inferred to be equal to 0.]]And the syntax structure picture_header_structure( ) is changed asfollows:

Descriptor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1) ...  if( deblocking_filter_[[override_enabled_flag]]mode_idc = = 3 &&dbf_info_in_ph_flag) {    ph_deblocking_filter_[[override]]used_flagu(1)    if( ph_deblocking_filter_[[override]]used_flag ) { ph_deblocking_[[filter_disabled]]parameters_override_flag u(1)     if([[!]]ph_deblocking_[[filter_disabled]]parameters_override_flag ) {     ph_beta_offset_div2 se(v)      ph_tc_offset_div2 se(v)     ph_cb_beta_offset_div2 se(v)      ph_cb_tc_offset_div2     ph_cr_beta_offset_div2 se(v)      ph_cr_tc_offset_div2 se(v)    }  }  } ...ph_deblocking.filter_used_flag equal to 1 specifies that the deblockingfilter is applied for the slices in the current picture.ph_deblocking_filter_used_flag equal to 0 specifies that the deblockingfilter is not applied for the slices in the current picture. When notpresent, the value of ph_deblocking_filter_used_flag is inferred to beequal to (deblocking_filter_mode_idc>0).ph_deblocking_[[flter]]parameters_override_flag equal to 1 specifiesthat deblocking parameters are present in thePH. ph_deblocking_[[filter]]parameters_override_flag equal to 0specifies that deblocking parameters are not present in the PH. When notpresent, the value of ph_deblocking_filter_override_flag is inferred tobe equal to 0.[[ph_deblocking_filter_disabled_flag equal to 1 specifies that theoperation of the deblocking filter is not applied for the slicesassociated with the PH. ph_deblocking_filter_disabled_flag equal to 0specifies that the operation of the deblocking filter is applied for theslices associated with the PH. When ph_deblocking_filter_disabled_flagis not present, it is inferred to be equal topps_deblocking_filter_disabled_flag.]]And the syntax structure slice_header( ) is changed as follows:

Descriptor slice_header( ) {  picture_header_in_slice_header_flag u(1)...   if( deblocking_filter_[[override_enabled_flag]]mode_idc = = 3 &&!dbf_info_in_ph_flag )    slice_deblocking_filter_[[override]]used_flagu(1)   if( slice_deblocking_filter_[[override]]used_flag ) {   slice_deblocking_[[filter_disabled]]parameters_override_flag u(1)   if( [[!]]slice_deblocking_[[filter_disabled]]parameters_override_flag) {     slice_beta_offset_div2 se(v)     slice_tc_offset_div2 se(v)    slice_cb_beta_offset_div2 se(v)     slice_cb_tc_offset_div2 se(v)    slice_cr_beta_offset_div2 se(v)     slice_cr_tc_offset_div2 se(v)   }   } ...

slice_deblocking_[[filter]]

_override_flag equal to 1 specifies that deblocking parameters arepresent in the slice header.slice_deblocking_[[filter]]parameters_override_flag equal to 0 specifiesthat deblocking parameters are not present in the slice header. When notpresent, the value of slice_deblocking_filter_override_flag is inferredto be equal to [[ph_deblocking_filter_override_flag]]

[[slice_deblocking_filter_disabled_flag equal to 1 specifies that theoperation of the deblocking filter is not applied for the current slice.slice_deblocking_filter_disabled_flag equal to 0 specifies that theoperation of the deblocking filter is applied for the current slice.When slice_deblocking_filter_disabled_flag is not present, it isinferred to be equal to ph_deblocking_filter_disabled_flag.]]And the decoding process of deblocking filter process is changed asfollows:

8.8.3 Deblocking Filter Process 8.8.3.1 General

The deblocking filter process is applied to all coding subblock edgesand transform block edges of a picture, except the following types ofedges:

-   -   Edges that are at the boundary of the picture,    -   Edges that coincide with the boundaries of a subpicture with        subpicture index subpicIdx and        loop_filter_across_subpic_enabled_flag[subpicIdx] is equal to 0,    -   Edges that coincide with the virtual boundaries of the picture        when VirtualBoundariesPresentFlag is equal to 1,    -   Edges that coincide with tile boundaries when        loop_filter_across_tiles_enabled_flag is equal to 0,    -   Edges that coincide with slice boundaries when        loop_filter_across_slices_enabled_flag is equal to 0,    -   Edges that coincide with upper or left boundaries of slices with        slice_deblocking_filter_        [[disabled]]_flag equal to [[1]]    -   Edges within slices with slice_deblocking_filter_        [[disabled]]_flag equal to [[1]]        ,    -   Edges that do not correspond to 4×4 sample grid boundaries of        the luma component,    -   Edges that do not correspond to 8×8 sample grid boundaries of        the chroma component,    -   Edges within the luma component for which both sides of the edge        have intra_bdpcm_luma_flag equal to 1,    -   Edges within the chroma components for which both sides of the        edge have intra_bdpcm_chroma_flag equal to 1,    -   Edges of chroma subblocks that are not edges of the associated        transform unit.        The edge type, vertical or horizontal, is represented by the        variable edgeType as specified in Table 42.        Table 42—Name of association to edgeType

edgeType Name of edgeType 0 (vertical edge) EDGE_VER 1 (horizontal edge)EDGE_HORWhen slice_deblocking_filter_

[[disabled]]_flag of the current slice is equal to [[0]]

, the following applies:

-   -   The variable treeType is set equal to DUAL_TREE_LUMA.    -   The vertical edges are filtered by invoking the deblocking        filter process for one direction as specified in clause 8.8.3.2        with the variable treeType, the reconstructed picture prior to        deblocking, i.e., the array recPicture_(L) and the variable        edgeType set equal to EDGE_VER as inputs, and the modified        reconstructed picture after deblocking, i.e., the array        recPicture_(L) as outputs.    -   The horizontal edge are filtered by invoking the deblocking        filter process for one direction as specified in clause 8.8.3.2        with the variable treeType, the modified reconstructed picture        after deblocking, i.e., the array recPicture_(L) and the        variable edgeType set equal to EDGE_HOR as inputs, and the        modified reconstructed picture after deblocking, i.e., the array        recPicture_(L) as outputs.    -   When ChromaArrayType is not equal to 0, the following applies:        -   The variable treeType is set equal to DUAL_TREE_CHROMA        -   The vertical edges are filtered by invoking the deblocking            filter process for one direction as specified in clause            8.8.3.2 with the variable treeType, the reconstructed            picture prior to deblocking, i.e., the arrays            recPicture_(Cb) and recPicture_(Cr), and the variable            edgeType set equal to EDGE_VER as inputs, and the modified            reconstructed picture after deblocking, i.e., the arrays            recPicture_(Cb) and recPicture_(Cr) as outputs.        -   The horizontal edge are filtered by invoking the deblocking            filter process for one direction as specified in clause            8.8.3.2 with the variable treeType, the modified            reconstructed picture after deblocking, i.e., the arrays            recPicture_(Cb) and recPicture_(Cr), and the variable            edgeType set equal to EDGE_HOR as inputs, and the modified            reconstructed picture after deblocking, i.e., the arrays            recPicture_(Cb) and recPicture_(Cr) as outputs.

6.3. Third Set of Embodiments

The changes, marked in

, are based on JVET-Q2001-vE.The i-th chroma QP mapping table ChromaQpTable[i] for i=0 . . .numQpTables−1 is derived as follows:

  qpInVal[ i ][ 0 ] = qp_table_start_minus26[ i ] + 26 qpOutVal[ i ][ 0] = qpInVal[ i ][ 0 ] for( j = 0; j <= num_points_in_qp_table_minus1[ i]; j++ ) {  qpInVal[ i ][ j + 1 ] = qpInVal[ i ][ j ] + delta_qp_in_val_minus1[ i ][ j ] + 1  qpOutVal[ i ][ j + 1 ] =qpOutVal[ i ][ j ] + ( (  delta_qp_in_val_minus1[ i ][ j ] + 1)  {circumflex over ( )} delta_qp_diff_val[ i ][ j ] ) } ChromaQpTable[ i][ qpInVal[ i ][ 0 ] ] = qpOutVal[ i ][ 0 ] for( k = qpInVal[ i ][ 0 ] −1; k >= −QpBdOffset; k − − )   ChromaQpTable[ i ][ k ] = Clip3(−QpBdOffset, 63,   ChromaQpTable[ i ][ k + 1 ] − 1 ) for( j = 0; j <=num_points_in_qp_table_minus1[ i ]; j++ ) {   sh = (delta_qp_in_val_minus1[ i ][j ] + 1 ) > > 1   for( k = qpInVal[ i ][ j] + 1, m = 1; k <=   qpInval[ i ][ j + 1 ]; k++, m++ )    ChromaQpTable[i ][ k ] =    ChromaQpTable[ i ][ qpInVal[ i ][ j ] ] +     ( (qpOutVal[ i ][j + 1] − qpOutVal[ i ][j ] ) * m + sh ) / (delta_qp_in_val_minus1[ i ][j] + 1 ) } for( k = qpInVal[ i ][num_points_in_qp_table_minus1[ i ] + 1 ] + 1; k <= 63; k++ )  ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset,   63, ChromaQpTable[ i][ k − 1 ] + 1 )When same_qp_table_for_chroma is equal to 1, ChromaQpTable[1][k] andChromaQpTable[2][k] are set equal to ChromaQpTable[0][k] for k in therange of −QpBdOffset to 63, inclusive.It is a requirement of bitstream conformance that the values ofqpInVal[i][j] and qpOutVal[i][j] shall be in the range of −QpBdOffset to63, inclusive for i in the range of 0 to numQpTables−1, inclusive, and jin the range of 0 to num_points_in_qp_table_minus1[i]+1, inclusive.

FIG. 1 is a block diagram showing an example video processing system1900 in which various techniques disclosed herein may be implemented.Various implementations may include some or all of the components of thesystem 1900. The system 1900 may include input 1902 for receiving videocontent. The video content may be received in a raw or uncompressedformat, e.g., 8 or 10 bit multi-component pixel values, or may be in acompressed or encoded format. The input 1902 may represent a networkinterface, a peripheral bus interface, or a storage interface. Examplesof network interface include wired interfaces such as Ethernet, passiveoptical network (PON), etc. and wireless interfaces such as wirelessfidelity (Wi-Fi) or cellular interfaces.

The system 1900 may include a coding component 1904 that may implementthe various coding or encoding methods described in the presentdocument. The coding component 1904 may reduce the average bitrate ofvideo from the input 1902 to the output of the coding component 1904 toproduce a coded representation of the video. The coding techniques aretherefore sometimes called video compression or video transcodingtechniques. The output of the coding component 1904 may be eitherstored, or transmitted via a communication connected, as represented bythe component 1906. The stored or communicated bitstream (or coded)representation of the video received at the input 1902 may be used bythe component 1908 for generating pixel values or displayable video thatis sent to a display interface 1910. The process of generatinguser-viewable video from the bitstream representation is sometimescalled video decompression. Furthermore, while certain video processingoperations are referred to as “coding” operations or tools, it will beappreciated that the coding tools or operations are used at an encoderand corresponding decoding tools or operations that reverse the resultsof the coding will be performed by a decoder.

Examples of a peripheral bus interface or a display interface mayinclude universal serial bus (USB) or high definition multimediainterface (HDMI) or Displayport, and so on. Examples of storageinterfaces include serial advanced technology attachment (SATA),peripheral component interconnect (PCI), integrated drive electronics(IDE) interface, and the like. The techniques described in the presentdocument may be embodied in various electronic devices such as mobilephones, laptops, smartphones or other devices that are capable ofperforming digital data processing and/or video display.

FIG. 2 is a block diagram of a video processing apparatus 3600. Theapparatus 3600 may be used to implement one or more of the methodsdescribed herein. The apparatus 3600 may be embodied in a smartphone,tablet, computer, Internet of Things (IoT) receiver, and so on. Theapparatus 3600 may include one or more processors 3602, one or morememories 3604 and video processing hardware 3606. The processor(s) 3602may be configured to implement one or more methods described in thepresent document. The memory (memories) 3604 may be used for storingdata and code used for implementing the methods and techniques describedherein. The video processing hardware 3606 may be used to implement, inhardware circuitry, some techniques described in the present document.

FIG. 4 is a block diagram that illustrates an example video codingsystem 100 that may utilize the techniques of this disclosure.

As shown in FIG. 4 , video coding system 100 may include a source device110 and a destination device 120. Source device 110 generates encodedvideo data which may be referred to as a video encoding device.Destination device 120 may decode the encoded video data generated bysource device 110 which may be referred to as a video decoding device.

Source device 110 may include a video source 112, a video encoder 114,and an input/output (I/O) interface 116.

Video source 112 may include a source such as a video capture device, aninterface to receive video data from a video content provider, and/or acomputer graphics system for generating video data, or a combination ofsuch sources. The video data may comprise one or more pictures. Videoencoder 114 encodes the video data from video source 112 to generate abitstream. The bitstream may include a sequence of bits that form acoded representation of the video data. The bitstream may include codedpictures and associated data. The coded picture is a codedrepresentation of a picture. The associated data may include sequenceparameter sets, picture parameter sets, and other syntax structures. I/Ointerface 116 may include a modulator/demodulator (modem) and/or atransmitter. The encoded video data may be transmitted directly todestination device 120 via I/O interface 116 through network 130 a. Theencoded video data may also be stored onto a storage medium/server 130 bfor access by destination device 120.

Destination device 120 may include an I/O interface 126, a video decoder124, and a display device 122.

I/O interface 126 may include a receiver and/or a modem. I/O interface126 may acquire encoded video data from the source device 110 or thestorage medium/server 130 b. Video decoder 124 may decode the encodedvideo data. Display device 122 may display the decoded video data to auser. Display device 122 may be integrated with the destination device120, or may be external to destination device 120 which be configured tointerface with an external display device.

Video encoder 114 and video decoder 124 may operate according to a videocompression standard, such as the High Efficiency Video Coding (HEVC)standard, Versatile Video Coding (VVC) standard and other current and/orfurther standards.

FIG. 5 is a block diagram illustrating an example of video encoder 200,which may be video encoder 114 in the system 100 illustrated in FIG. 4 .

Video encoder 200 may be configured to perform any or all of thetechniques of this disclosure. In the example of FIG. 5 , video encoder200 includes a plurality of functional components. The techniquesdescribed in this disclosure may be shared among the various componentsof video encoder 200. In some examples, a processor may be configured toperform any or all of the techniques described in this disclosure.

The functional components of video encoder 200 may include a partitionunit 201, a prediction unit 202 which may include a mode select unit203, a motion estimation unit 204, a motion compensation unit 205 and anintra prediction unit 206, a residual generation unit 207, a transformunit 208, a quantization unit 209, an inverse quantization unit 210, aninverse transform unit 211, a reconstruction unit 212, a buffer 213, andan entropy encoding unit 214.

In other examples, video encoder 200 may include more, fewer, ordifferent functional components. In an example, prediction unit 202 mayinclude an intra block copy (IBC) unit. The IBC unit may performprediction in an IBC mode in which at least one reference picture is apicture where the current video block is located.

Furthermore, some components, such as motion estimation unit 204 andmotion compensation unit 205 may be highly integrated, but arerepresented in the example of FIG. 5 separately for purposes ofexplanation.

Partition unit 201 may partition a picture into one or more videoblocks. Video encoder 200 and video decoder 300 may support variousvideo block sizes.

Mode select unit 203 may select one of the coding modes, intra or inter,e.g., based on error results, and provide the resulting intra- orinter-coded block to a residual generation unit 207 to generate residualblock data and to a reconstruction unit 212 to reconstruct the encodedblock for use as a reference picture. In some example, Mode select unit203 may select a combination of intra and inter prediction (CIIP) modein which the prediction is based on an inter prediction signal and anintra prediction signal. Mode select unit 203 may also select aresolution for a motion vector (e.g., a sub-pixel or integer pixelprecision) for the block in the case of inter-prediction.

To perform inter prediction on a current video block, motion estimationunit 204 may generate motion information for the current video block bycomparing one or more reference frames from buffer 213 to the currentvideo block. Motion compensation unit 205 may determine a predictedvideo block for the current video block based on the motion informationand decoded samples of pictures from buffer 213 other than the pictureassociated with the current video block.

Motion estimation unit 204 and motion compensation unit 205 may performdifferent operations for a current video block, for example, dependingon whether the current video block is in an I slice, a P slice, or a Bslice.

In some examples, motion estimation unit 204 may perform uni-directionalprediction for the current video block, and motion estimation unit 204may search reference pictures of list 0 or list 1 for a reference videoblock for the current video block. Motion estimation unit 204 may thengenerate a reference index that indicates the reference picture in list0 or list 1 that contains the reference video block and a motion vectorthat indicates a spatial displacement between the current video blockand the reference video block. Motion estimation unit 204 may output thereference index, a prediction direction indicator, and the motion vectoras the motion information of the current video block. Motioncompensation unit 205 may generate the predicted video block of thecurrent block based on the reference video block indicated by the motioninformation of the current video block.

In other examples, motion estimation unit 204 may perform bi-directionalprediction for the current video block, motion estimation unit 204 maysearch the reference pictures in list 0 for a reference video block forthe current video block and may also search the reference pictures inlist 1 for another reference video block for the current video block.Motion estimation unit 204 may then generate reference indexes thatindicate the reference pictures in list 0 and list 1 containing thereference video blocks and motion vectors that indicate spatialdisplacements between the reference video blocks and the current videoblock. Motion estimation unit 204 may output the reference indexes andthe motion vectors of the current video block as the motion informationof the current video block. Motion compensation unit 205 may generatethe predicted video block of the current video block based on thereference video blocks indicated by the motion information of thecurrent video block.

In some examples, motion estimation unit 204 may output a full set ofmotion information for decoding processing of a decoder.

In some examples, motion estimation unit 204 may not output a full setof motion information for the current video. Rather, motion estimationunit 204 may signal the motion information of the current video blockwith reference to the motion information of another video block. Forexample, motion estimation unit 204 may determine that the motioninformation of the current video block is sufficiently similar to themotion information of a neighboring video block.

In one example, motion estimation unit 204 may indicate, in a syntaxstructure associated with the current video block, a value thatindicates to the video decoder 300 that the current video block has thesame motion information as another video block.

In another example, motion estimation unit 204 may identify, in a syntaxstructure associated with the current video block, another video blockand a motion vector difference (MVD). The motion vector differenceindicates a difference between the motion vector of the current videoblock and the motion vector of the indicated video block. The videodecoder 300 may use the motion vector of the indicated video block andthe motion vector difference to determine the motion vector of thecurrent video block.

As discussed above, video encoder 200 may predictively signal the motionvector. Two examples of predictive signaling techniques that may beimplemented by video encoder 200 include advanced motion vectorprediction (AMVP) and merge mode signaling.

Intra prediction unit 206 may perform intra prediction on the currentvideo block. When intra prediction unit 206 performs intra prediction onthe current video block, intra prediction unit 206 may generateprediction data for the current video block based on decoded samples ofother video blocks in the same picture. The prediction data for thecurrent video block may include a predicted video block and varioussyntax elements.

Residual generation unit 207 may generate residual data for the currentvideo block by subtracting (e.g., indicated by the minus sign) thepredicted video block(s) of the current video block from the currentvideo block. The residual data of the current video block may includeresidual video blocks that correspond to different sample components ofthe samples in the current video block.

In other examples, there may be no residual data for the current videoblock for the current video block, for example in a skip mode, andresidual generation unit 207 may not perform the subtracting operation.

Transform processing unit 208 may generate one or more transformcoefficient video blocks for the current video block by applying one ormore transforms to a residual video block associated with the currentvideo block.

After transform processing unit 208 generates a transform coefficientvideo block associated with the current video block, quantization unit209 may quantize the transform coefficient video block associated withthe current video block based on one or more quantization parameter (QP)values associated with the current video block.

Inverse quantization unit 210 and inverse transform unit 211 may applyinverse quantization and inverse transforms to the transform coefficientvideo block, respectively, to reconstruct a residual video block fromthe transform coefficient video block. Reconstruction unit 212 may addthe reconstructed residual video block to corresponding samples from oneor more predicted video blocks generated by the prediction unit 202 toproduce a reconstructed video block associated with the current blockfor storage in the buffer 213.

After reconstruction unit 212 reconstructs the video block, loopfiltering operation may be performed reduce video blocking artifacts inthe video block.

Entropy encoding unit 214 may receive data from other functionalcomponents of the video encoder 200. When entropy encoding unit 214receives the data, entropy encoding unit 214 may perform one or moreentropy encoding operations to generate entropy encoded data and outputa bitstream that includes the entropy encoded data.

FIG. 6 is a block diagram illustrating an example of video decoder 300which may be video decoder 124 in the system 100 illustrated in FIG. 4 .

The video decoder 300 may be configured to perform any or all of thetechniques of this disclosure. In the example of FIG. 6 , the videodecoder 300 includes a plurality of functional components. Thetechniques described in this disclosure may be shared among the variouscomponents of the video decoder 300. In some examples, a processor maybe configured to perform any or all of the techniques described in thisdisclosure.

In the example of FIG. 6 , video decoder 300 includes an entropydecoding unit 301, a motion compensation unit 302, an intra predictionunit 303, an inverse quantization unit 304, an inverse transformationunit 305, and a reconstruction unit 306 and a buffer 307. Video decoder300 may, in some examples, perform a decoding pass generally reciprocalto the encoding pass described with respect to video encoder 200 (FIG. 5).

Entropy decoding unit 301 may retrieve an encoded bitstream. The encodedbitstream may include entropy coded video data (e.g., encoded blocks ofvideo data). Entropy decoding unit 301 may decode the entropy codedvideo data, and from the entropy decoded video data, motion compensationunit 302 may determine motion information including motion vectors,motion vector precision, reference picture list indexes, and othermotion information. Motion compensation unit 302 may, for example,determine such information by performing the AMVP and merge mode.

Motion compensation unit 302 may produce motion compensated blocks,possibly performing interpolation based on interpolation filters.Identifiers for interpolation filters to be used with sub-pixelprecision may be included in the syntax elements.

Motion compensation unit 302 may use interpolation filters as used byvideo encoder 200 during encoding of the video block to calculateinterpolated values for sub-integer pixels of a reference block. Motioncompensation unit 302 may determine the interpolation filters used byvideo encoder 200 according to received syntax information and use theinterpolation filters to produce predictive blocks.

Motion compensation unit 302 may use some of the syntax information todetermine sizes of blocks used to encode frame(s) and/or slice(s) of theencoded video sequence, partition information that describes how eachmacroblock of a picture of the encoded video sequence is partitioned,modes indicating how each partition is encoded, one or more referenceframes (and reference frame lists) for each inter-encoded block, andother information to decode the encoded video sequence.

Intra prediction unit 303 may use intra prediction modes for examplereceived in the bitstream to form a prediction block from spatiallyadjacent blocks. Inverse quantization unit 303 inverse quantizes, i.e.,de-quantizes, the quantized video block coefficients provided in thebitstream and decoded by entropy decoding unit 301. Inverse transformunit 303 applies an inverse transform.

Reconstruction unit 306 may sum the residual blocks with thecorresponding prediction blocks generated by motion compensation unit302 or intra-prediction unit 303 to form decoded blocks. If desired, adeblocking filter may also be applied to filter the decoded blocks inorder to remove blockiness artifacts. The decoded video blocks are thenstored in buffer 307, which provides reference blocks for subsequentmotion compensation/intra prediction and also produces decoded video forpresentation on a display device.

A listing of examples preferred by some embodiments is provided next.

The first set of clauses show example embodiments of techniquesdiscussed in the previous section. The following clauses show exampleembodiments of techniques discussed in the previous section (e.g., item1).

-   -   1. A video processing method (e.g., method 3000 shown in FIG. 3        ), comprising: performing (3002) a conversion between a video        having one or more chroma components, the video comprising one        or more video pictures comprising one or more slices and a coded        representation of the video, wherein the coded representation        conforms to a format rule, wherein the format rule specifies        that a chroma array type field controls a constraint on a        conversion characteristic of chroma used during the conversion.    -   2. The method of clause 1, wherein the conversion characteristic        includes a constraint on a field indicative of presence of one        or more scaling lists for the one or more chroma components.    -   3. The method of clause 1, wherein the conversion characteristic        includes a constraint on a value of a field indicative of a        codeword used for signaling luma mapping with chroma scaling.    -   4. The method of clause 1, wherein the conversion characteristic        includes a constraint on values of syntax elements describing an        adaptation parameter set for an adaptive loop filter used during        the conversion.    -   5. The method of clause 1, wherein the format rule specifies to        use a same semantics of one or more entries of an adaptation        parameter set for the chroma array type field signaling a 4:0:0        format or a separate color coding format.    -   6. The method of clause 5, wherein the one or more entries        include an adaptive loop filter parameter or a scaling list        parameter or a luma mapping with chroma scaling parameter.    -   7. The method of clauses 5-6, wherein the format rule further        specifies that a constraint on the one or more entries of the        adaptation parameter set is dependent on whether an identifier        of the adaptation parameter set is included in the bitstream.

The following clauses show example embodiments of techniques discussedin the previous section (e.g., item 2).

-   -   8. A video processing method, comprising: performing a        conversion between a video comprising one or more video pictures        comprising one or more video regions and a coded representation        of the video, wherein the coded representation conforms to a        format rule that specifies the include a deblocking mode        indicator for a video region indicative of applicability of a        deblocking filter to the video region during the conversion.    -   9. The method of clause 8, wherein the deblocking mode indicator        is an N bit field where N is an integer greater than 1.    -   10. The method of any of clauses 8-9, wherein the deblocking        mode indicator for the video region is included in a picture        parameter set.    -   11. The method of clause 8, wherein the deblocking mode        indicator corresponds to a flag included in a header of the        video region indicating applicability of the deblocking filter        to the video region.    -   12. The method of any of clauses 8-11, wherein the format rule        specifies that a flag that signals whether deblocking filter        parameters signaled in the deblocking mode indicator are to        override default parameters.    -   13. The method of any of clauses 8-12, wherein the video region        corresponds to a video picture or a video slice.

The following clauses show example embodiments of techniques discussedin the previous section (e.g., item 3).

-   -   14. A video processing method, comprising: performing a        conversion between a video comprising one or more video pictures        comprising one or more video slices and/or one or more video        subpictures and a coded representation of the video, wherein the        coded representation conforms to a format rule that specifies        that a flag indicating whether a single slice per subpicture        mode is deemed to be enabled for a video picture in case that a        picture partitioning is disabled for the video picture.

The following clauses show example embodiments of techniques discussedin the previous section (e.g., item 4).

-   -   15. A video processing method, comprising: performing a        conversion between a video comprising one or more video pictures        comprising one or more video slices and a coded representation        of the video, wherein the coded representation conforms to a        format rule that specifies that a picture or a slice level        chroma quantization parameter offset is signaled in a picture        header or a slice header.    -   16. The method of clause 15, wherein the format rule specifies        to include slice level chroma quantization parameter offsets in        the slice header.

The following clauses show example embodiments of techniques discussedin the previous section (e.g., item 5).

-   -   17. A video processing method, comprising: performing a        conversion between a video comprising one or more video pictures        comprising one or more video slices and a coded representation        of the video, wherein the coded representation conforms to a        format rule that specifies that a chroma quantization parameter        (QP) table applicable for conversion of a video block of the        video is derived as an XOR operation between        (delta_qp_in_val_minus1[i][j]+1) and delta_qp_diff_val[i][j],        wherein delta_qp_in_val_minus1[i][j] specifies a delta value        used to derive the input coordinate of the j-th pivot point of        the i-th chroma mapping table and delta_qp_diff_val[i][j]        specifies a delta value used to derive the output coordinate of        the j-th pivot point of the i-th chroma QP mapping table, where        i and j are integers.    -   18. The method of any of clauses 1 to 17, wherein the conversion        comprises encoding the video into the coded representation.    -   19. The method of any of clauses 1 to 17, wherein the conversion        comprises decoding the coded representation to generate pixel        values of the video.    -   20. A video decoding apparatus comprising a processor configured        to implement a method recited in one or more of clauses 1 to 19.    -   21. A video encoding apparatus comprising a processor configured        to implement a method recited in one or more of clauses 1 to 19.    -   22. A computer program product having computer code stored        thereon, the code, when executed by a processor, causes the        processor to implement a method recited in any of clauses 1 to        19.    -   23. A method, apparatus or system described in the present        document.

A second set of clauses show example embodiments of techniques discussedin the previous section (e.g., items 2, 4, 5 and 6).

-   -   1. A method of video processing (e.g., method 700 as shown in        FIG. 7A), comprising: performing 702 a conversion between a        video comprising a picture and a bitstream of the video        according to a format rule, and wherein the format rule        specifies that a presence of a syntax element in a sequence        parameter set that indicates a constrain on loop filtering        across subpicture boundaries is based on whether a number of        subpictures in the picture is greater than 1.    -   2. The method of clause 1, wherein the syntax element equal to a        certain value specifies that all subpicture boundaries in a        coded layer video sequence are treated as picture boundaries and        there is no loop filtering across the subpicture boundaries.    -   3. The method of clause 1 or 2, wherein the syntax element is        sps_independent_subpics_flag.    -   4. The method of clause any of 1 to 3, wherein the syntax        element is present only in case that the number of subpictures        in the picture is greater than 1.    -   5. The method of clause any of clause 1 to 4, wherein the syntax        element is not present in case that the number of subpictures in        the picture is equal to 1.    -   6. The method of clause 2, wherein the format rule specifies        that, in case that the syntax element is not present, a value of        the syntax element is inferred to be equal to the certain value.    -   7. The method of clause 2 or 6, wherein the certain value is        equal to 1.    -   8. The method of clause 1, wherein the format rule specifies        that, in case that the syntax element is not present, a value of        the syntax element is inferred based on another syntax element.    -   9. The method of clause 5, wherein another syntax element        corresponds to a subpicture information present flag indicating        whether subpicture information is present or not.    -   10. The method of clause 5, wherein the value of the syntax        element is inferred based on a value of a subpicture information        present flag indicating whether subpicture information is        present or not.    -   11. A method of video processing (e.g., method 710 as shown in        FIG. 7B), comprising: performing 712 a conversion between a        video comprising one or more pictures and a bitstream of the        video according to a format rule, and wherein the format rule        specifies how to infer a value of a syntax element that is not        present, wherein the syntax element related to treating a        subpicture as a picture for excluding in-loop filtering        operations.    -   12. The method of clause 11, wherein the syntax element        indicates whether to treat an i-th subpicture of each picture in        a coded layer video sequence is treated as a picture in an        encoding or a decoding process excluding in-loop filtering        operations.    -   13. The method of clause 11 or 12, wherein the syntax element is        subpic_treated_as_pic_flag[i].    -   14. The method of clause 11 or 13, wherein the format rule        specifies that, in case that the syntax element is not present,        a value of the syntax element is inferred to be equal to a        certain value that specifies the i-th subpicture of each coded        picture in the coded layer video sequence is treated as a        picture in an encoding or a decoding process excluding in-loop        filtering operations.    -   15. The method of clause 14, wherein certain value is equal to        1.    -   16. The method of any of clause 11 to 13, wherein in case that        the syntax element is not present, the value of the syntax        element is inferred to be equal to a certain value to enable a        wrap-around motion compensation.    -   17. The method of any of clauses 11 to 13, wherein in case that        the syntax element is not present, the value of the syntax        element is inferred to be equal to a certain value to enable a        horizontal wrap-around motion compensation.    -   18. The method of clause 11 to 13, wherein the format rule        specifies that the value of the syntax element is inferred based        on whether the picture only consists of one subpicture and/or        whether a subpicture has a same width as the picture.    -   19. The method of clause 11 to 13, wherein the format rule        specifies that the value of the syntax element is inferred based        on i) a presence of subpicture information and/or ii) a number        of subpictures in the coded layer video sequence and/or iii)        another syntax element in a sequence parameter set that        indicates a constrain on loop filtering across subpicture        boundaries.    -   20. A method of video processing (e.g., method 720 as shown in        FIG. 7C), comprising: performing 722 a conversion between a        video comprising one or more video regions and a bitstream of        the video according to a format rule, and wherein the format        rule specifies that a sequence parameter set includes syntax        elements that are related to parameters of a deblocking filter        applicable to a video region.    -   21. The method of clause 20, wherein the syntax elements include        a syntax element specifying an applicability of the deblocking        filter for the video region.    -   22. The method of clause 20 or 21, wherein the format rule        specifies, in case that the deblocking filter is disabled in the        sequence parameter set, that a syntax element in a picture        parameter set, a picture header, a slice header that relates to        the deblocking filter control has a value equal to a certain        value specifying that the deblocking filter is fully disabled        and not used for all slices.    -   23. The method of clause 20, wherein the syntax elements include        a deblocking filter control present flag that specifies a        presence of the syntax elements.    -   24. The method of clause 20, wherein the syntax elements include        a deblocking mode indicator that is an N bit field where N is an        integer greater than 1.    -   25. The method of clause 20, wherein the syntax elements include        values of deblocking parameters t_(c) and ß.    -   26. The method of clause 20, wherein the format rule specifies        that the syntax elements in the sequence parameter set controls        whether the deblocking filter is enabled with 0-valued        deblocking parameters.    -   27. The method of clause 20, wherein the format rule specifies        to apply the deblocking filter at a sequence parameter set level        or a picture parameter set level or a picture header level or a        slice header level and use deblocking parameters included in the        sequence parameter set.    -   28. The method of clause 20, wherein the format rule specifies        to apply the deblocking filter at a sequence parameter set level        or a picture parameter set level or a picture header level or a        slice header level and use 0-valued deblocking parameters        included in the sequence parameter set.    -   29. A method of video processing (e.g., method 730 as shown in        FIG. 7D), comprising: performing a conversion between a video        comprising one or more pictures comprising one or more slices        and a bitstream of the video according to a format rule, wherein        the format rule specifies that a luma quantization parameter        delta information and/or a chroma quantization parameter offset        is included in both a picture header and a slice header in case        that a certain condition is met.    -   30. The method of clause 29, wherein the format rule further        specifies that a luma quantization parameter delta present flag        indicating a presence of the luma quantization parameter delta        information is included in at least one of the picture parameter        set, the picture header, or the slice header.    -   31. The method of clause 30, wherein whether the certain        condition is met is dependent on the luma quantization parameter        delta present flag.    -   32. The method of clause 30 or 31, wherein the format rule        specifies that values of the luma quantization parameter delta        information in the picture header and the slice header are        additive used for calculating a luma quantization parameter.    -   33. The method of clause 29, wherein the format rule further        specifies that a chroma quantization parameter offsets present        flag indicating a presence of the chroma quantization parameter        offset is included in at least one of the picture parameter set,        the picture header, or the slice header.    -   34. The method of clause 33, wherein whether the certain        condition is met is dependent on the chroma quantization        parameter offsets present flag.    -   35. The method of clause 33, wherein the format rule specifies        that values of the chroma quantization parameter offsets in the        picture header and the slice header are additive used for        calculating a chroma quantization parameter.    -   36. A method of video processing, comprising: performing a        conversion between a video comprising one or more video pictures        comprising one or more video slices and a bitstream of the video        according to a format rule, wherein the format rule specifies        that a chroma quantization parameter (QP) table applicable for        conversion of a video block of the video is derived as an XOR        operation between (delta_qp_in_val_minus1[i][j]+1) and        delta_qp_diff_val[i][j], wherein delta_qp_in_val_minus1[i][j]        specifies a delta value used to derive the input coordinate of        the j-th pivot point of the i-th chroma mapping table and        delta_qp_diff_val[i][j] specifies a delta value used to derive        the output coordinate of the j-th pivot point of the i-th chroma        QP mapping table, where i and j are integers.    -   37. A method of video processing (e.g., method 740 as shown in        FIG. 7E), comprising: performing 742 a conversion between a        video comprising one or more video pictures comprising one or        more video slices and a bitstream of the video according to a        format rule, and wherein the format rule specifies to include a        flag indicating a presence of multiple sets of chroma        quantization parameter tables in a sequence parameter set.    -   38. The method of clause 37, wherein the format rule specifies        that the flag is equal to 0 in case that only one set of the        chroma quantization parameter tables is allowed to be signaled.    -   39. The method of clause 37, wherein the format rule specifies        that the flag is equal to 1 in case that the multiple sets of        the chroma quantization parameter tables are allowed to be        signaled.    -   40. A method of video processing (e.g., method 750 as shown in        FIG. 7F), comprising: performing a conversion between a video        comprising one or more video pictures comprising one or more        video slices and a bitstream of the video according to a format        rule, and wherein the format rule specifies that indication of        multiple sets of chroma quantization parameter tables is        disabled for a sequence due to the sequence not including a        slice of a particular type.    -   41. The method of clause 40, wherein the particular type is a B        slice type.    -   42. The method of clause 40, wherein the particular type is a P        slice type.    -   43. The method of any of clauses 1 to 42, wherein the conversion        includes encoding the video into the bitstream.    -   44. The method of any of clauses 1 to 42, wherein the conversion        includes decoding the video from the bitstream.    -   45. The method of clauses 1 to 42, wherein the conversion        includes generating the bitstream from the video, and the method        further comprises: storing the bitstream in a non-transitory        computer-readable recording medium.    -   46. A video processing apparatus comprising a processor        configured to implement a method recited in any one or more of        clauses 1 to 45.    -   47. A method of storing a bitstream of a video, comprising, a        method recited in any one of clauses 1 to 45, and further        including storing the bitstream to a non-transitory        computer-readable recording medium.    -   48. A computer readable medium storing program code that, when        executed, causes a processor to implement a method recited in        any one or more of clauses 1 to 45.    -   49. A computer readable medium that stores a bitstream generated        according to any of the above described methods.    -   50. A video processing apparatus for storing a bitstream        representation, wherein the video processing apparatus is        configured to implement a method recited in any one or more of        clauses 1 to 45.

A third set of clauses show example embodiments of techniques discussedin the previous section (e.g., items 7-9).

-   -   1. A method of video processing (e.g., method 800 as shown in        FIG. 8A), comprising: making 802 a determination, for a        conversion between a video region of a video and a bitstream of        the video, about how padding or clipping is performed for an        inter-prediction process at a boundary of the video region        according to a rule; and performing 804 the conversion based on        the determination; wherein the rule is based on at least two        of (a) a type of the boundary, (b) a first parameter indicative        of whether a wrap-around motion compensation is enabled, or (c)        a second parameter indicating whether subpicture boundaries are        treated as picture boundaries.    -   2. The method of clause 1, wherein the rule specifies to apply        the wraparound motion compensation during the inter-prediction        process without considering the second parameter in case that        the boundary is a picture boundary and that the first parameter        is equal to a certain value.    -   3. The method of clause 1 or 2, wherein the boundary is a        vertical boundary.    -   4. The method of clause 1 or 2, wherein the boundary type is a        picture boundary.    -   5. The method of clause 1 or 2, wherein the boundary type is a        subpicture boundary.    -   6. The method of clause 1 or 2, wherein the first parameter is a        syntax flag at a picture parameter set level that specifies        whether a horizontal wrap-around motion compensation is enabled        for pictures referring to the picture parameter set.    -   7. The method of clause 1 or 2, wherein the second parameter is        a syntax flag at a sequence parameter set that specifies whether        a subpicture of each coded picture in a coded layer video        sequence is treated as a picture in a decoding process excluding        in-loop filtering operations.    -   8. The method of clause 1, wherein the rule specifies to apply        the wrap-around motion compensation during the inter-prediction        process without considering the second parameter in case that        both two vertical boundaries are picture boundaries and that the        first parameter is equal to a certain value.    -   9. The method of any of clauses 1 to 8, wherein the wrap-around        motion compensation indicates horizontal wrap around padding or        clipping.    -   10. A method of video processing (e.g., method 810 as shown in        FIG. 8B), comprising: performing 812 a conversion between a        video comprising one or more pictures and a bitstream of the        video according to a format rule, wherein the format rule        specifies that offsets for wrap around padding or clipping for        subpictures of a picture are specified at a subpicture level.    -   11. The method of clause 10, wherein the format rule specifies        to include different indications for the wrap around padding or        clipping for the subpictures.    -   12. The method of clause 10, wherein the format rule specifies        to include different offsets for the wrap around padding or        clipping for the subpictures.    -   13. The method of any of clauses 1 to 12, wherein the conversion        includes encoding the video into the bitstream.    -   14. The method of any of clauses 1 to 12, wherein the conversion        includes decoding the video from the bitstream.    -   15. The method of clauses 1 to 12, wherein the conversion        includes generating the bitstream from the video, and the method        further comprises: storing the bitstream in a non-transitory        computer-readable recording medium.    -   16. A video processing apparatus comprising a processor        configured to implement a method recited in any one or more of        clauses 1 to 15.    -   17. A method of storing a bitstream of a video, comprising, a        method recited in any one of clauses 1 to 15, and further        including storing the bitstream to a non-transitory        computer-readable recording medium.    -   18. A computer readable medium storing program code that, when        executed, causes a processor to implement a method recited in        any one or more of clauses 1 to 15.    -   19. A computer readable medium that stores a bitstream generated        according to any of the above described methods.    -   20. A video processing apparatus for storing a bitstream,        wherein the video processing apparatus is configured to        implement a method recited in any one or more of clauses 1 to        15.

A fourth set of clauses show example embodiments of techniques discussedin the previous section (e.g., item 10)

-   -   1. A method of video processing (e.g., method 900 as shown in        FIG. 9 ), comprising: performing 902 a conversion between a        video comprising one or more video regions and a bitstream of        the video according to a format rule, wherein the format rule        specifies that a variable X indicates whether B slice is allowed        or used in a video region, and wherein the format rule further        specifies that the variable X is based on values of a reference        picture list information present flag and/or a field indicating        a number of entries in a reference picture list syntax        structure.    -   2. The method of clause 1, wherein the video region corresponds        to a picture or a slice.    -   3. The method of clause 1 or 2, wherein the reference picture        list information present flag is in a picture header.    -   4. The method of any of clauses 1 to 3, wherein the reference        picture list information present flag is rpl_info_in_ph_flag and        the field indicating the number of entries in the reference        picture list syntax structure is num_ref_entries [i][RplsIdx        [i]], and wherein the variable X is derived using at least one        of following:        -   a) (rpl_info_in_ph_flag && num_ref_entries[0][RplsIdx[0]]>0            && num_ref_entries[1][RplsIdx[1]]>0);        -   b) (rpl_info_in_ph_flag &&            num_ref_entries[1][RplsIdx[1]]>0);        -   c) (rpl_info_in_ph_flag &&            num_ref_entries[1][RplsIdx[1]]>1);        -   d) (rpl_info_in_ph_flag &&            num_ref_entries[1][RplsIdx[1]]>0);        -   e) based on a number of active reference indices to be used            for a slice; or        -   f) based on a number of allowed reference pictures for list            1, whereby i is an integer.    -   5. The method of any of clauses 1 to 4, wherein the format rule        further specifies that signaling and/or semantics and/or        inference of one or more syntax elements included in the syntax        structure corresponding to a picture header is dependent on the        variable X.    -   6. The method of clause 5, wherein the one or more syntax        elements enable a coding tool which requires more than one        prediction signal.    -   7. The method of clause 6, wherein the coding tool corresponds        to a bi-prediction, a mixed intra and inter coding, or        prediction with linear or non-linear weighting from multiple        prediction blocks.    -   8. The method of clause 6, wherein the one or more syntax        elements include a first syntax element indicating whether        collocated pictures used for temporal motion vector prediction        is derived from a reference picture list 0 or reference picture        list 1, a second syntax element indicating whether motion vector        difference coding syntax structure for list 1 is parsed or not,        a third syntax element indicating whether a bi-directional        optical flow coding is disabled, a fourth syntax element        indicating whether a decoder-side motion vector refinement is        disabled, a fifth syntax element indicating a number of weights        signalled for entries in the reference picture list 1.    -   9. The method of clause 8, wherein the first syntax element        corresponds to ph_collocated_from_l0_flag, the second syntax        element corresponds to ph_mvd_11_zero_flag, the third syntax        element corresponds to ph_disable_bdof_flag, the fourth syntax        element corresponds to ph_disable_dmvr_flag, and the fifth        syntax element corresponds to num_11_weights.    -   10. The method of clause 5, wherein the format rule further        specifies that, only in case that the variable X indicates that        the picture contains one or more B slices, the one or more        syntax elements are included.    -   11. The method of clause 5, wherein the format rule further        specifies that in case that the variable X indicates that the        picture contains no B slices, the one or more syntax elements        are skipped.    -   12. The method of clause 5, wherein the format rule further        specifies whether to signal the one or more syntax elements are        based on the variable X.    -   13. The method of clause 5, wherein the format rule further        specifies that when the variable X is equal to 0 and a syntax        element indicating whether motion vector difference coding        syntax structure is parsed or not is not signaled, a value of        the syntax element is inferred to be equal to a certain value.    -   14. The method of clause 13, wherein the format rule further        specifies that when the variable X being set to        “rpl_info_in_ph_flag” is equal to 0, the value of the syntax        element is inferred to be equal to 1.    -   15. The method of clause 13, wherein the format rule further        specifies that when the variable X being set to        “num_ref_entries[1][RplsIdx[1]]>0” is equal to 0, the value of        the syntax element is inferred to be equal to 1.    -   16. The method of clause 5, wherein the format rule further        specifies that the inference of the one or more syntax elements        is dependent on a value of the variable X.    -   17. The method of clause 16, wherein the one or more syntax        elements include a PH (picture header) syntax element indicating        whether a bi-directional optical flow coding is disabled and        wherein the format rule specifies that a value of the PH syntax        element is inferred based on the value of the variable X.    -   18. The method of clause 16, wherein the one or more syntax        elements include a PH (picture header) syntax element indicating        whether a decoder-side motion vector refinement is disabled and        wherein the format rule specifies that a value of the PH syntax        element is inferred based on the value of the variable X.    -   19. The method of clause 16, wherein the one or more syntax        elements include a PH (picture header) syntax element indicating        whether collocated pictures used for temporal motion vector        prediction is derived from a reference picture list 1 or a        reference picture list 0 and wherein the format rule specifies        that a value of the PH syntax element is inferred to be equal to        a certain value in case of satisfying (1) a value of another PH        syntax element indicating an applicability of temporal motion        vector predictor to a picture is equal to 1, (2) a value of the        reference picture list information present flag in a picture        header is equal to 1, and (3) the value of the variable X is        equal to 0.    -   20. The method of clause 19, wherein the value of the PH        (picture header) syntax element is inferred to be equal to 0 in        case of satisfying (1) the value of another PH syntax element        indicating the applicability of temporal motion vector predictor        to the picture is equal to 1, (2) the value of the reference        picture list information present flag in a picture header is        equal to 1, and (3) the variable X being set to        “num_ref_entries[1][RplsIdx[1]]>0” is equal to 0.    -   21. The method of clause 16, wherein the one or more syntax        elements include a PH (picture header) syntax element indicating        a number of weights signalled for entries in the reference        picture list land wherein the format rule specifies that a value        of the PH syntax element is inferred to be equal to a certain        value in case that the variable X is equal to a certain value.    -   22. The method of clause 21, wherein the value of the PH syntax        element is inferred to be equal to 0 in case that the variable X        being set to “num_ref_entries[1][RplsIdx[1]]>0” is equal to 0.    -   23. The method of clause 22, wherein when the value of the PH        syntax element is inferred to be equal to 0, weighted prediction        parameters for the reference picture list 1 are not signalled in        a picture header or slice headers of a picture.    -   24. The method of any of clauses 1 to 23, wherein the conversion        includes encoding the video into the bitstream.    -   25. The method of any of clauses 1 to 23, wherein the conversion        includes decoding the video from the bitstream.    -   26. The method of clauses 1 to 23, wherein the conversion        includes generating the bitstream from the video, and the method        further comprises: storing the bitstream in a non-transitory        computer-readable recording medium.    -   27. A video processing apparatus comprising a processor        configured to implement a method recited in any one or more of        clauses 1 to 26.    -   28. A method of storing a bitstream of a video, comprising, a        method recited in any one of clauses 1 to 26, and further        including storing the bitstream to a non-transitory        computer-readable recording medium.    -   29. A computer readable medium storing program code that, when        executed, causes a processor to implement a method recited in        any one or more of clauses 1 to 26.    -   30. A computer readable medium that stores a bitstream generated        according to any of the above described methods.    -   31. A video processing apparatus for storing a bitstream        representation, wherein the video processing apparatus is        configured to implement a method recited in any one or more of        clauses 1 to 26.

In the present document, the term “video processing” may refer to videoencoding, video decoding, video compression or video decompression. Forexample, video compression algorithms may be applied during conversionfrom pixel representation of a video to a corresponding bitstreamrepresentation or vice versa. The bitstream representation of a currentvideo block may, for example, correspond to bits that are eitherco-located or spread in different places within the bitstream, as isdefined by the syntax. For example, a macroblock may be encoded in termsof transformed and coded error residual values and also using bits inheaders and other fields in the bitstream. Furthermore, duringconversion, a decoder may parse a bitstream with the knowledge that somefields may be present, or absent, based on the determination, as isdescribed in the above solutions. Similarly, an encoder may determinethat certain syntax fields are or are not to be included and generatethe coded representation accordingly by including or excluding thesyntax fields from the coded representation.

The disclosed and other solutions, examples, embodiments, modules andthe functional operations described in this document can be implementedin digital electronic circuitry, or in computer software, firmware, orhardware, including the structures disclosed in this document and theirstructural equivalents, or in combinations of one or more of them. Thedisclosed and other embodiments can be implemented as one or morecomputer program products, i.e., one or more modules of computer programinstructions encoded on a computer readable medium for execution by, orto control the operation of, data processing apparatus. The computerreadable medium can be a machine-readable storage device, amachine-readable storage substrate, a memory device, a composition ofmatter effecting a machine-readable propagated signal, or a combinationof one or more them. The term “data processing apparatus” encompassesall apparatus, devices, and machines for processing data, including byway of example a programmable processor, a computer, or multipleprocessors or computers. The apparatus can include, in addition tohardware, code that creates an execution environment for the computerprogram in question, e.g., code that constitutes processor firmware, aprotocol stack, a database management system, an operating system, or acombination of one or more of them. A propagated signal is anartificially generated signal, e.g., a machine-generated electrical,optical, or electromagnetic signal, that is generated to encodeinformation for transmission to suitable receiver apparatus.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this document can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., a field programmable gate array (FPGA) or anapplication specific integrated circuit (ASIC).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random-access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Computer readable media suitable for storingcomputer program instructions and data include all forms of non-volatilememory, media and memory devices, including by way of examplesemiconductor memory devices, e.g., erasable programmable read-onlymemory (EPROM), electrically erasable programmable read-only memory(EEPROM), and flash memory devices; magnetic disks, e.g., internal harddisks or removable disks; magneto optical disks; and compact disc,read-only memory (CD ROM) and digital versatile disc read-only memory(DVD-ROM) disks. The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

While the present disclosure contains many specifics, these should notbe construed as limitations on the scope of any subject matter or ofwhat may be claimed, but rather as descriptions of features that may bespecific to particular embodiments of particular techniques. Certainfeatures that are described in the present disclosure in the context ofseparate embodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Moreover, the separation of various system components in theembodiments described in the present disclosure should not be understoodas requiring such separation in all embodiments.

Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on whatis described and illustrated in the present disclosure.

1. A method of video processing, comprising: performing a conversionbetween a video comprising one or more video regions and a bitstream ofthe video according to a format rule, wherein the format rule specifiesthat a presence of a first syntax element in a sequence parameter setthat indicates a constrain on loop filtering across subpictureboundaries is based on whether a number of subpictures in a picture isgreater than 1, wherein the first syntax element equal to 1 specifiesthat all of the subpicture boundaries in a coded layer video sequenceare treated as picture boundaries and there is no loop filtering acrossthe subpicture boundaries, wherein the first syntax element is notpresent in case that the number of subpictures in the picture is equalto 1, and wherein in case that the first syntax element is not present,a value of the first syntax element is inferred to be equal to
 1. 2. Themethod of claim 1, wherein the format rule further specifies that incase that a second syntax element is not present, a value of the secondsyntax element is inferred to be equal to 1 that specifies an i-thsubpicture of each coded picture in the coded layer video sequence istreated as a picture in an encoding or a decoding process excludingin-loop filtering operations, wherein i is an integer.
 3. The method ofclaim 2, wherein the format rule further specifies that during aninter-prediction process, how clipping is performed at a boundary of avideo region of the one or more video regions is based on a third syntaxelement at a picture parameter set level, specifying whether ahorizontal wrap-around motion compensation is enabled for picturesreferring to a picture parameter set and the second syntax element at asequence parameter set level.
 4. The method of claim 1, wherein theformat rule further specifies that a fourth syntax element indicateswhether a bi-directional optical flow inter prediction based interbi-prediction is disabled for a video region of the one or more videoregions, and wherein the format rule further specifies that a presencein a picture header of the fourth syntax element is based on values of afifth syntax element which is a reference picture list informationpresent flag that indicates whether reference picture list informationis present in the picture header and a sixth syntax element indicating anumber of entries in a reference picture list syntax structure.
 5. Themethod of claim 4, wherein the video region corresponds to a picture ora slice.
 6. The method of claim 4, wherein the fifth syntax element isrpl_info_in_ph_flag and the sixth syntax element isnum_ref_entries[i][RplsIdx [i]], wherein i is an integer, and whereinthe fourth syntax element is present in the picture header at leastbased on (rpl_info_in_ph_flag && num_ref_entries[1][RplsIdx[1]]>0),wherein num_ref_entries[1][RplsIdx[1]] indicates that the number ofentries in the RplsIdx[1]-th reference picture list syntax structure fora reference picture list
 1. 7. The method of claim 6, wherein the fourthsyntax element being present in the picture header is further based on avalue of a seventh syntax element indicating that the fourth syntaxelement is allowed to be present.
 8. The method of claim 4, wherein theformat rule further specifies that a presence in the picture header ofan eighth syntax element indicating whether a decoder-side motion vectorrefinement is disabled is based on the values of the fifth syntaxelement and the sixth syntax element.
 9. The method of claim 8, whereinthe eighth syntax element is present in the picture header, when a valueof a ninth syntax element indicates that the eighth syntax element isallowed to be present, a value of the fifth syntax elementrpl_info_in_ph_flag is equal to 1 and a value of the sixth syntaxelement num_ref_entries[1][RplsIdx[1]] is greater than
 1. 10. The methodof claim 4, wherein the format rule further specifies that a presence inthe picture header of a tenth syntax element indicating whether motionvector difference coding syntax structure for list 1 is parsed or not isat least based on that a value of the fifth syntax elementrpl_info_in_ph_flag is equal to 1 and a value of the sixth syntaxelement num_ref_entries[1][RplsIdx[1]] is greater than
 1. 11. The methodof claim 4, wherein the format rule further specifies that a presence inthe picture header of an eleventh syntax element indicating whethercollocated pictures used for temporal motion vector prediction isderived from a reference picture list 0 or reference picture list 1 isat least based on that a value of the fifth syntax elementrpl_info_in_ph_flag is equal to 1 and a value of the sixth syntaxelement num_ref_entries[1][RplsIdx[1]] is greater than
 1. 12. The methodof claim 11, wherein the format rule further specifies that when a valueof a twelfth syntax element indicates that a temporal motion vectorpredictor is enabled, the value of the fifth syntax elementrpl_info_in_ph_flag is equal to 1 and the value of the sixth syntaxelement num_ref_entries[1][RplsIdx[1]] is equal to 0, the value of theeleventh syntax element is inferred to be equal to 1 which indicatesthat the collocated pictures used for temporal motion vector predictionis derived from the reference picture list
 0. 13. The method of claim 4,wherein the format rule further specifies that a presence in the pictureheader of a thirteenth syntax element indicating a number of weightssignalled for entries in a reference picture list 1 is at least based onthat a value of the fifth syntax element rpl_info_in_ph_flag is equal to1 and a value of the sixth syntax element num_ref_entries[1][RplsIdx[1]]is greater than
 1. 14. The method of claim 1, wherein the conversionincludes encoding the video into the bitstream.
 15. The method of claim1, wherein the conversion includes decoding the video from thebitstream.
 16. An apparatus for processing video data comprising aprocessor and a non-transitory memory with instructions thereon, whereinthe instructions upon execution by the processor, cause the processorto: perform a conversion between a video comprising one or more videoregions and a bitstream of the video according to a format rule, whereinthe format rule specifies that a presence of a first syntax element in asequence parameter set that indicates a constrain on loop filteringacross subpicture boundaries is based on whether a number of subpicturesin a picture is greater than 1, wherein the first syntax element equalto 1 specifies that all of the subpicture boundaries in a coded layervideo sequence are treated as picture boundaries and there is no loopfiltering across the subpicture boundaries, wherein the first syntaxelement is not present in case that the number of subpictures in thepicture is equal to 1, and wherein in case that the first syntax elementis not present, a value of the first syntax element is inferred to beequal to
 1. 17. The apparatus of claim 16, wherein the format rulefurther specifies that in case that a second syntax element is notpresent, a value of the second syntax element is inferred to be equal to1 that specifies an i-th subpicture of each coded picture in the codedlayer video sequence is treated as a picture in an encoding or adecoding process excluding in-loop filtering operations, wherein i is aninteger, wherein the format rule further specifies that during aninter-prediction process, how clipping is performed at a boundary of avideo region of the one or more video regions is based on a third syntaxelement at a picture parameter set level, specifying whether ahorizontal wrap-around motion compensation is enabled for picturesreferring to a picture parameter set and the second syntax element at asequence parameter set level.
 18. A non-transitory computer-readablestorage medium storing instructions that cause a processor to: perform aconversion between a video comprising one or more video regions and abitstream of the video according to a format rule, wherein the formatrule specifies that a presence of a first syntax element in a sequenceparameter set that indicates a constrain on loop filtering acrosssubpicture boundaries is based on whether a number of subpictures in apicture is greater than 1, wherein the first syntax element equal to 1specifies that all of the subpicture boundaries in a coded layer videosequence are treated as picture boundaries and there is no loopfiltering across the subpicture boundaries, wherein the first syntaxelement is not present in case that the number of subpictures in thepicture is equal to 1, and wherein in case that the first syntax elementis not present, a value of the first syntax element is inferred to beequal to
 1. 19. The non-transitory computer-readable storage medium ofclaim 18, wherein the format rule further specifies that in case that asecond syntax element is not present, a value of the second syntaxelement is inferred to be equal to 1 that specifies an i-th subpictureof each coded picture in the coded layer video sequence is treated as apicture in an encoding or a decoding process excluding in-loop filteringoperations, wherein i is an integer, wherein the format rule furtherspecifies that during an inter-prediction process, how clipping isperformed at a boundary of a video region of the one or more videoregions is based on a third syntax element at a picture parameter setlevel, specifying whether a horizontal wrap-around motion compensationis enabled for pictures referring to a picture parameter set and thesecond syntax element at a sequence parameter set level.
 20. Anon-transitory computer-readable recording medium storing a bitstream ofa video which is generated by a method performed by a video processingapparatus, wherein the method comprises: generating, for the videocomprising one or more video regions, the bitstream of the videoaccording to a format rule, wherein the format rule further specifiesthat a presence of a first syntax element in a sequence parameter setthat indicates a constrain on loop filtering across subpictureboundaries is based on whether a number of subpictures in a picture isgreater than 1, wherein the first syntax element equal to 1 specifiesthat all of the subpicture boundaries in a coded layer video sequenceare treated as picture boundaries and there is no loop filtering acrossthe subpicture boundaries, wherein the first syntax element is notpresent in case that the number of subpictures in the picture is equalto 1, and wherein in case that the first syntax element is not present,a value of the first syntax element is inferred to be equal to 1.